Final Report Summary - SUSREF (Sustainable refurbishment of building facades and external walls)
Executive summary:
SUSREF developed technologies and methodologies for sustainable refurbishment of external walls. SUSREF was based on the premise that:
1) refurbishment of external walls is one of the most efficient ways of reducing environmental impacts of European building stock;
2) European building sector is facing huge needs of renovation; refurbishment of external walls is among the most urgent tasks;
3) Although there are technological solutions, the risks and optimal solutions are not fully understood;
4) External walls have an extensive effect on building performance and several aspects have to be taken into account when developing new concepts.
5) Urgent needs of refurbishment are not only faced in the EU but also in neighboring areas; development of functional and environmentally efficient technologies would support the European industry to export projects and the neighboring areas to adopt sustainable technologies.
The objective of the project was to:
1) identify the needs to refurbish building envelops in the EU to understand the significance in terms of environmental and economic impacts;
2) develop a systemized method to manage the functional performance of solutions;
3) develop sustainable product concepts;
4) disseminate results for building industry, standardisation bodies, and policy-makers in terms of technological knowledge, guidelines and recommendations.
SUSREF assessed the potential savings in energy and costs with help of using scenarios for the refurbishment of external walls. The total investment cost was assessed to be 28000 million euro/year directed for the energy related refurbishment. On the other hand the savings in energy costs were assessed to be 2500 million euro/year. The difference in annual Life Cycle Cost is in average -11 000 million euro within 20 years. In addition, it was assessed that the corresponding increase of labor would be 396000 man years/year. The estimated potential CO2 savings is 72 Mt/y.
It was defined that the overall sustainability of the developed concepts and technological solutions of the project has to be assessed considering the following aspects:
1) Durability,
2) Impact on energy demand for heating,
3) Impact on energy demand for cooling,
4) Impact on renewable energy use potential,
5) Impact on daylight,
6) Environmental impact of manufacture and maintenance,
7) Indoor air quality and acoustics,
8) Structural stability,
9) Fire safety,
10) Aesthetic quality,
11) Effect on cultural heritage,
12) Life cycle costs,
13) Need for care and maintenance,
14) Disturbance to the tenants and to the site,
15) Buildability.
Project Context and Objectives:
The starting point of the SUSREF project was as follows:
1) The Refurbishment of the external walls of any building is one of the most efficient ways of improving the environmental impacts of the European building stock.
2) The age of the build structure in the European building stock is causing a situation where the building sector and building owners are facing the extensive challenge of refurbishing many of the buildings. The renovation and refurbishment of the building facades and external walls are among the most urgent tasks to be undertaken.
3) Although there are technological solutions for refurbishment of external walls, the risks and optimal solutions of the new concepts are not fully understood. In order to avoid creating early problems in the energy renovation of buildings, the new concepts and solutions cannot be used without achieving a comprehensive understanding about the building/s physical behaviour, the products and the optimal solutions with regard to energy efficiency and environmental impacts.
4) External walls have an extensive effect on building performance and several aspects have to be taken into account when developing new concepts for refurbishment. An optimal approach should consider the following aspects: a) effect on energy consumption, b) building physical behaviour and durability, c) good integration with building structure, details and building services, d) effect on indoor environment and comfort, e) aesthetics.
5) The urgent need of good building refurbishment methods are not only faced in the EU but also - even more greatly - in neighboring areas and other parts of the world. The development of functional and environmentally efficient technologies and concepts would support the European industry in exporting technology and projects, and to support and advise the neighboring areas to adopt more sustainable technologies.
This project aimed at creating the following outputs:
- inform building industry about the optimal sustainable technologies available and potential of these technologies
- guide and inform standardisation bodies about the comprehensive sustainability performance of building external walls, giving recommendations on how this should be considered in the further development of CPD related product specifications and sustainable building standardisation
- inform policy makers about the overall significance of building external walls in the progression of the European building stock towards sustainable performance.
The main objectives of the SUSREF project were:
1) to identify and understand the volume of need to refurbish the building envelops in the EU and in neighboring areas. To understand the meaning of these needs in the first place in terms of environmental impacts and secondly in terms of economic impact and business potential;
2) to develop a systemized theory and differing technologies when refurbishing building facades and external walls in order to ensure the functional excellence of solutions. To analyse technologies from the view point of building physics, comfort and energy efficiency. To consider the various challenges in different parts of Europe in terms of present climate and foreseen risks of changes, technological differences, and cultural-historic differences. And finally to deliver sets of relevant performance specifications for sustainable refurbishment;
3) to develop systemized methods for consideration of environmental performance of external walls. To assess and ensure the sustainability of the developed technologies in terms of environmental impacts, life cycle costs, social and cultural impacts;
4) to develop sustainable concepts for carrying out refurbishments projects;
5) to disseminate the results for a) building industry, b) standardisation bodies, and c) policy-makers and authorities in terms of technological knowledge, guidelines and recommendations.
The existing methodologies and knowledge on which the project was based include the following:
1) Modeling of solutions for the refurbishment of façades and external walls
2) Technological solutions developed for the refurbishment of facades
3) Life cycle assessment methods
4) Knowledge management methods and tools for optimisation
5) Building physical and energy models
There have been attempts to model refurbishment solutions. The project made use of these existing models and further develop those in order to better suit for the wider comprehensive target of the project. The project made use of the existing and advanced technological solutions, and analysed, modeled, improved and developed concepts so that selection can be done considering the regional and localised climatic conditions, ensuring good functionality and optimising the energy and environmental efficiency.
LCA is a technique for assessing the environmental aspects and potential impacts with a product by compiling an inventory of relevant inputs and outputs of a product system, evaluating the potential environmental impacts associated with those inputs and outputs and interpreting the results of the inventory analysis and impact assessment phases in relation to the objectives of the study. General guidelines are given in ISO standards 14040 and 14044 and in the International Life Cycle System Handbook. Rules for the environmental declaration of building products are given in ISO 21930. Life cycle costing (LCC) is a technique for estimating the cost of whole buildings, systems and/or building components and materials, and for monitoring the occurred cots and impacts throughout the building life. The technique can assist decision-making in building investment projects. LCC is used to evaluate the cost performance of a building throughout its lifecycle, including acquisition, development, operation, management, repair, disposal, and decommissioning. In addition to internationally agreed standards and guidelines, there are a number of national and specific methodologies for integrated life-cycle management of buildings. SUSREF applied the existing life cycle assessment methods for the assessment of refurbishment concepts.
Building physical models have been developed for the analysis and assessment of building physical behavior and energy performance. These are assessment and simulation models that cover moisture dynamics in building envelopes, computational simulation of heat, air and moisture transport in materials and constructions and the hygrothermal interaction between the materials of building envelope and surrounding climate. These models enable assessment of a layout in respect to e.g. effects on indoor air, moisture buffering, air flow patterns near surface and risk of mould growth. Some of the tools concentrate on single building components, as building envelope (MATCH), and others on the whole building performance (WUFI+). Many of the common models, however, concern only heat transfer problems and are multidimensional tools for analysing thermal bridges (HEAT2). Also on the building level, the simulation of energy performance is dominating (EnergyPlus). The purpose of these models is to support the achievement of energy efficient and durable constructions and good indoor air quality.
The aim of the project was also to study and summarise relevant standards for sustainable renovations that might need revision and recommendations for standardisation bodies. Relevant standards are in the fields of:
- environmental assessment of building products and buildings,
- life cycle costing,
- service life assessment.
The CE marking is based on a harmonised product standard (hEN) or a European Technical Approval (ETA). The European Technical Approval granted only by a member body of the European Organisation for the Technical Approvals, EOTA. The building materials which used in renovation and refurbishment are CE-marked now according to the same rules as the products used in new constructions. For the harmonized standards to be relevant for refurbishment work, it would be necessary that the intended use of the product includes refurbishment and that all relevant material properties are declared.
The product-related requirements are described in the relevant technical product standard and for renovation and refurbishment products there are no individual separate technical standards exists. Products used in renovation and refurbishment should fulfill the same requirements that products used in new construction. On the other hand new materials and product concepts will be developed with new properties for the renovation and refurbishment market. New, technical standards and test methods may be necessary to accommodate to these new products. For these cases the building material industry needs to take the standardization initiative towards to the members of CEN committee who then launches the preparation work for new standard. The process for new standards already exists and even this is quite long lasting procedure there is no need for new working method (standard procedure) for renovation materials use.
In the transformation of buildings to sustainability, governmental authorities may play different roles:
- As a governor through the launch of control and regulatory instruments.
- As developer including green procurement specifications in housing developments and public buildings.
- Acting as a demonstrator or "early adopter" of new solutions demonstrating the validity and viability of new solutions in pilot buildings or their own property buildings
- Acting as a mobilizer of the sector, promoting the implementation of concepts or solutions through economic and market based instruments rewarding, incentivizing, and introducing direct subsidies.
In addition to the coming legislation and regulations that will be based on the recast energy performance directive, there is also a need to develop other instruments than control and regulatory instruments. Especially fiscal instruments and incentives and informative support will be needed in order to:
- to achieve common willingness among public to make efforts for significantly improved quality and energy performance of exterior walls of buildings
- to avoid risks in the connection of building renovations
- to economically facilitate choices that are excellent from the view point of technical and long-term sustainability reasons.
Project Results:
Main S&T results
SUSREF developed
- information about the significance of the refurbishment of exterior walls of the European building stock. The significance was assessed in terms of potential energy savings, CO2 savings, life cycle costs and labor.
- a systemized approach for the assessment and development of refurbishment concepts for exterior walls. This approach includes assessment criteria and detailed guidelines for assessment methods.
- general and specific refurbishment concepts and their assessment results
- guidelines for refurbishment projects and building industry
- recommendations for standardisation bodies and policy makers.
Significance of the refurbishment of exterior walls
The total wall areas of the European residential building stock were summarised based on earlier research data (IMPRO 2008). The estimated façade areas are 12600 million m2 for single family houses and 4450 million m2 for multifamily and high rise buildings. The potential of the refurbishment of exterior walls was assessed in terms of estimated savings in energy use, GHG emissions, life cycle costs and labor.
The assumed maximal potential of SUSREF concepts in Europe was as follows:
-Adding new/more insulation will be relevant for 4060% of the building stock during 10 years depending on building age and climate zone
-Stone walls are not usually be insulated outside but in the case of an extensive renovation.
-Demolition of 5% of the present building stock will take place during the next 10 years.
-Increase of 7% of present building stock will take place during the next 10 years.
The walls already insulated or replaced by new ones have not been included to the volumes of potential refurbishments. Some energy saving actions will be done also for those during the next 10 years but the relative importance of those actions is small.
For a certain number of buildings there are either no possibilities or needs to make external changes (25-50% of the building stock built before 1945 (because of aesthetic and cultural reasons) and 20-40% of the building stock built after 1970 (because the walls are in good condition).
When calculating walls to be refurbished life-cycle optimized comprehensive concept was preferred instead of separate actions.
The assessed volumes of refurbishment are bigger than what has been the case during the last 10 years. The explanation for this choice is that it was thought that the different new steering mechanisms will accelerate the building refurbishment projects. The project assessed the potential effects of the refurbishment of exterior walls in terms of GHG emissions, costs and labor. The result was assessed with the help of the description of refurbishment concepts and scenarios for the realization of refurbishments. The total investment cost was assessed to be 28000 million euro/year directed for the energy related refurbishment. The savings in energy costs were assessed to be 2500 million euro/year. The difference in annual Life Cycle Cost is in average -11 000 million euro within 20 years. In addition, it was assessed that the corresponding increase of labor would be 396000 man years/year. The estimated GHG saving was 72 Mt/y.
Systematic approach for the assessment of refurbishment concepts
The following list shows the final sustainability assessment criteria defined by the SUSREF project. These criteria together with the related assessment methods define the systematic approach for the sustainability assessment of refurbishment concepts of exterior walls. On the basis of the discussion it was defined that the overall sustainability of the developed concepts and technological solutions of the project will be assessed considering the following 15 aspects:
-Durability
-Impact on energy demand for heating
-Impact on energy demand for cooling
-Impact on renewable energy use potential
-Impact on daylight
-Environmental impact of manufacture and maintenance
-Indoor air quality and acoustics
-Structural stability
-Fire safety
-Aesthetic quality
-Effect on cultural heritage
-Life cycle costs
-Need for care and maintenance
-Disturbance to the tenants and to the site
-Buildability
Although the importance of different aspects vary with practical circumstances and with the desires and requirements of clients, the consideration of all aspects is important. Some of the aspects should be studied quantitatively in order to give an adequate understanding about the impacts. These aspects are Durability, Impact on energy demand, Environmental impact and Life Cycle costs. The list also covers important aspects related to construction and operational processes (Disturbance, Buildability and Need for care and maintenance). The list covers the most important functional performance aspects of exterior walls (Structural stability, Fire safety, Aesthetic quality, impact on Indoor environment). The usability of the approach requires the definition of assessment methods for different aspects. The recommended assessment methods are carefully described in SUSREF deliverables. The defined methods for durability, energy performance, environmental impacts and life cycle costs are simulation and calculation methods.
According to SUSREF conclusions the building physical development process can be seen as an iteration process where the best solution for any actual case is found by optimizing:
1) thermal performance of the envelope: reduction of the heat losses through the envelope, minimising thermal bridges,
2) moisture performance of the envelope: ensuring drying capacity, avoiding condensation,
3) durability of the constructions: reduction of the risk for mould, decay, frost and corrosion,
4) indoor air quality and comfort: thermal symmetry, no draft, control of humidity.
Dynamic simulations with hygrothermal simulation tools are an important part of the assessment work. Depending on the construction type and refurbishment method to be analysed, the most suitable calculation and simulation tools should be chosen. One-dimensional (1D) coupled heat and moisture calculations tools are the best choice for constructions and solutions consisting of just homogenous layers. Ventilated cavities can be studied simplified with these tools, too. Two-dimensional (2D) coupled heat and moisture calculations tools should be used for constructions containing inhomogeneous layers, e.g. stone walls, fastenings, and ventilation cavities. Generally, 1D-tools are sufficient for most of the analysis with skilled expert use. The computation of coupled heat and moisture transport in two dimensions is usually time-consuming and the detailed information from a 2D or even 3D calculation may be overruled by other uncertainties.
General refurbishment concepts
SUSREF developed both general and specific refurbishment concepts for exterior walls. The study combined different refurbishment technologies into four main groups. The technologies differ from each other mainly by the manner in how placement of new insulation layers would be normally undertaken. The primary technologies for refurbishing external wall are:
-Technologies for replacing existing walls (R)
-Technologies for applying external (insulation) layers (E)
-Technologies for inserting (insulation) materials in cavities in existing walls (C)
-Technologies for applying internal insulation (I).
The overall results are presented in Deliverable D4.2 and in SUSREF Final report Par B General refurbishment concepts. The concepts were assessed from the view point of the selected 15 criteria as explained in the section Systematic approach for the assessment of refurbishment concepts. The following buildings types are covered in the development and assessment of the generic concepts:
-Small houses
-Terraced houses
-Multi-storey Apartments/Flats.
The original wall types considered in the assessment of the generic refurbishment concepts are as follows:
-Solid wall (brick, natural stone)
-Sandwich element (concrete panel + concrete panel)
-Load bearing wood structure (wooden frame)
-Insulated load bearing cavity (concrete block + concrete block)
-Load bearing cavity without insulation (brick + concrete block)
-Load bearing wood structure (wooden frame)
-Non-load bearing cavity (hollow brick + perforated brick)
-Non-load bearing concrete block without insulation (hollow brick + concrete block).
The generic concepts were assessed analytically and when relevant, using a parametric approach. This means that each performance aspect of the generic concepts will be assessed by dealing with relevant issues as parameters. Relevant issues are very much determined by specific performance aspects, and these could be different in many issues. Relevant issues may be for example be Quality and performance properties of materials, Thickness of insulation and other layers, Existence of air cavity, Fixing mechanisms, Quality of surface material, Condition of the existing structure, and Rainfalls and temperatures.
Building physical assessment and Durability
The main principle of designing and constructing wall structures is that the wall must be airtight and the water vapor permeability of structural layers increases gradually towards the outside surface of a wall. A water vapor barrier may be needed near the inner surface of a wall, if the water vapor permeability of materials is too high and the materials can't absorb all the extra moisture or the moisture levels inside the wall may become too high. Rain water leakages into wall structures through defected joints and construction faults are harmful. If the insulation material is foam plastic or other water vapor tight material or if the insulation material is such that can absorb very little moisture, water leakages are especially harmful. The leaked water causes the biggest problems with mineral wool insulated timber frame walls. Excessive moisture levels may cause mould or rotting of timber parts.
There are some principals that help the design for good durability:
-ensure that walls and their joints are airtight and the water vapor permeability of structural layers increases gradually towards the outside surface of a wall
-it is more effective to add retrofit insulation on the outer surface of a wall and the risks of moisture condensation and accumulation in the existing wall are lower
-the thicker retrofit insulation on the exterior surface of a wall the better
-the thicker retrofit insulation on the inner surface of a wall the worse
-use materials and structures that are known to be durable
-ensure, that the old wall can hold the extra weight of retrofit part and if not, add extra bindings and fixings to the old wall
-design the structure and it's joints, sealings and supports carefully
-prevent driven rain water to flow into a wall structure and especially to the warmer side of a cellular plastic thermal insulation
-ensure the water tightness of joints between window, wall and external window sill
-control manufacturing and installation
-make inspections periodically
-repair found defects in time
Different refurbishment concepts of building facades and external walls were analysed for possible long-term degradation. The analyses were conducted for the climate conditions of various European climates and with various outer core materials and thermal insulations. Degradation models used were as follows:
Frost attack
VTT simulation software assesses the occurrence and propagation of frost damage is evaluated based on the theory of critical degree of saturation developed by [Goran Fagerlund 1977]. Frost damage is assumed to take place when the moisture content of concrete exceeds the critical water saturation and the temperature descends below the freezing point at the same time.
Carbonation and corrosion
The model used to evaluate the rate of corrosion on the reinforcement includes an initiation period and a propagation period. Initiation of corrosion is assumed to take place when carbonation reaches the depth of reinforcement. Both the rate of carbonation and the rate of corrosion depend on the temperature and moisture content of concrete.
Mould growth
Numerical simulation of mould growth can be used as one of the hygrothermal performance criteria for the building structures. Mould is one of the first signs of too high moisture content of materials and it may affect the indoor air quality and also the appearance of the visible surfaces. Mould growth potential can be predicted by solving a numerical value, mould growth index, by using the dynamic temperature and relative humidity histories of the subjected material surfaces. The model was originally based on mould growth on wooden materials but has now been completed with several other building materials. The model can be used parallel with heat, air and moisture simulation models or as a post-processing tool.
Environmental impact
Environmental impact assessment focuses on the impact of non-renewable energy (energy transmission through the wall and energy consumption of refurbishment materials), non-renewable raw materials (from energy production and refurbishment materials) and especially released greenhouse gases and thus carbon footprint. Main parameters which were used for the assessment of environmental impact and for different wall renovation concepts were:
-Material type (insulation, façade) and properties (specific weight, consumption, thermal conductivity, environmental impact)
-Existing wall type, deterioration rate and corresponding U-value
-Renovation concept and target U-value
-Building location and heating degree days
-Heating type and environmental impact from heating
-Material service lives and need for maintenance.
Environmental impact in the connection of building renovations depends on the existing building type, building condition and renovation concept used. In typical building design, where the shape of building is square and rectangular, the exterior walls form 1.2 - 1.5 wall-m2/one floor-m2. Wall structures can be divided to light, medium and massive structures and when the used material amount is high, normally also environmental impact are higher compared to lightweight cases. The same principle is applicable also to renovation concepts; the lighter the structure is typically the smaller are the environmental impacts of the concept. At the same time, exterior walls are responsible for the heat transmission and thus have an effect to the total energy performance. Because of that, the impact from renovation materials should be studied alongside with the heat transmission and heating type. Depending on the existing building types, the additional insulation can be placed to the existing wall either externally, internally or into the wall cavity. This study focused mainly on the external and internal renovation cases because the material consumption remains small in the case of cavity walls and doesn't cause so significant effect in terms of energy saving and environmental impact. However, cavity walls are included when the renovation is performed internally or externally. The examples are given for chosen building types to illustrate the ability of energy saving building renovation and environmental impact.
In the case of external renovation, where façade is installed with the presence of air gap, different new façade materials can be used. Façade types studied in this survey were concrete, wood and clay brick façades.
The best façade material in terms of environmental impacts (carbon footprint, non-renewable raw material and - energy consumption), was wooden façade. This renovation concept is a light weight option, wood is a renewable raw material and timber production utilizes by-product energy which also renewable.
In the regions where heating period is long (Northern Europe), the materials used in wall renovation can cause up to 40% of total carbon footprint (20 year operation). This result refers to a case where mineral wool with 3-layer rendering façade was used and heating energy was produced with the Nordel electricity mix (where renewable energy share is high).
For the U-value 0.21 W/m2K, the materials share from total CF is roughly 10 - 15% but it varies depending on heating types. In the case of U-value 0.1 it is varies between roughly 30-40%. The material share can be higher, when high share of heating energy is produced from renewable resources.
Present study shows that exterior wall renovation can achieve big reduction in energy saving measures and environmental impact. Which renovation option is suitable and best in particular cases should be determined considering the overall building condition, historical background and building neighborhood and region. Walls form only one part of the buildings and impacts should be assessed also on building level.
Life cycle costing
The Life Cycle costing covers only extra costs and energy cost caused by refurbishment. The analysis includes price of money (+ 2%/y). Economic assessment is based on the calculation of life cycle cost according to ISO 15686-5. The results are presented in terms of net present values. This is calculated by summing up the activated costs in different years for present with present unit costs (without discount rate). The energy costs were calculated considering the realistic increase of costs. The present value methodology means summing up of the activated costs in different years for present either with present unit costs or taking the foreseen realized costs (usually energy cost) into account.
The refurbishment concepts were compared to a basic case in order to understand more clearly the different effect of material and structure selections. The results show that it is not profitable to improve the thermal insulation of an external wall if the outer layer of the wall doesn't need repair. If the energy price increase rate is high, the refurbishment may become profitable.
Specific refurbishment concepts
The 6 SME partners of the project improved and developed concepts for the refurbishment of exterior walls. The work focused on the chosen common walls types, building types and refurbishment technologies. The research organisations and universities of the project carried out assessments in accordance with the chosen approach.
Altogether 16 refurbishment concepts were developed. The refurbishment concepts developed by the SMEs are listed in the following:
1 Brick wall with ventilation gap and vacuum insulated panel
2 Re-SOLAR (structural solutions collect solar energy and both retain it for the heating and protect the building from overheating)
3 ETICS applied to sandwich element
4 ETICS (External thermal insulation composite systems) applied to sandwich element internal layer
5 ETICS applied to insulated panel RUS (RUS refers to possible areas of application)
6 ETICS applied to solid panel RUS
7 Filling brick wall cavities with carbamide resin foam
8 Thermo-reflective multi-foil outer insulation of brick wall with controllable ventilation air gap before insulation
9 Exterior refurbishment of wooden frame walls with a flex system board insulation
10 Transparent insulation
11 External insulation of solid rubble stone wall with vapor-open natural insulation material and ventilated timber cladding
12 External insulation of solid rubble stone wall with semi-vapor-open mineral wool insulation material and acrylic render
13 External insulation of solid rubble stone wall with expanded polystyrene insulation material and acrylic render
14 External shelter of solid rubble stone wall with unventilated dark-colored steel sheet cladding
15 Internal insulation vapour-open of solid rubble stone wall with lime-sand pointing outside
16 Load bearing ventilated façade
The following information was developed for all concepts.
-cross section figures of the existing wall
-cross section figures of the refurbishment solution
-material layers and thicknesses
-working methods
-areas of suitable application
-known problems related to refurbishment method
-market potential.
Usability of the systematic approach
The starting point of the project was that a systematic approach is needed especially for SMEs when they start to improve refurbishment concepts and develop new concepts. The systematic approach was found feasible and useful because it supported the product concept developers to:
-iterate and optimize material and structural choices
-compare alternative solutions
-investigate the feasibility of new and innovative solutions
-avoid risks
-assess long-term impacts both from the view point of building performance and environmental and financials impacts
-consider both functionality and process related aspects
-develop systems with help of which clients are supported to set targets for refurbishment works.
Tools for decision making sustainable refurbishment of outdoor walls
The main objective in developing the tool was to provide an efficient and effective tool for the practitioner, such as the architects, designers and building contractors, in order to identify alternatives for technical solutions for sustainable refurbishment. The developed tool offers quick access to a number of refurbishment solutions studied in the project and leads to detailed information about how suitable and buildable the solutions are. The criteria included in the tool are: Durability, Care and maintenance, Indoor climate, Heating energy, Cooling energy, Renewables, Environment, LCC, Aesthetic quality, Cultural heritage, Structural stability, Fire safety, Buildability, Disturbance, Daylight . Qualitative scales for each of the 15 criteria were prepared and linked to the first level of the tool. See the following table. The table shows an example of a qualitative scale for retrofitting insulation regarding maintenance needs and vulnerability to damage.
Sets of performance specifications
SUSREF project developed concepts for the refurbishment of exterior walls. The project developed both generic concepts as well as specific concepts. The specific concepts were developed considering specific buildings markets and geographical conditions. The specific concepts are introduced with help of the tool SUSREF SPECIFICATIONS. This document presents the contents and the operating principles of the tool:
Outline of concepts
Guidelines for building industry
Mainly on the basis of Task 4.2 outcomes, the project developed guidelines for building industry. The guidelines are presented in Deliverable 7.4 and in SUSRE Final report Part A. The short summary of the guidelines is as follows:
The focus of the work was to pay attention to some of the main findings and results of the previous more thorough technical analysis reports on the refurbishment concepts. The material presented includes summaries and conclusions of several analyses. Only the main results of some topics are given here, the background analysis may be found from the technical reports (mainly report D4.2). These topics have high industrial relevance and the results may be, to a large extent, utilised as recommendations for refurbishment projects. The use of the SUSREF approach is recommended, this approach relates to the following aspects: Durability, need for care and maintenance, indoor air quality, acoustics + thermal comfort, impact on energy demand for heating and cooling, impact on renewable energy use potential, environmental impact of manufacture and maintenance, life cycle costs, aesthetic quality, effect on cultural heritage, structural stability, fire safety, buildability, disturbance to the tenants and to the site and impact on daylight.
As guidelines to the industry when developing concepts for the refurbishment of external walls, the following recommendations are given.
The building physical performance of the wall has to be checked with suitable methods (as given in D2.2). The main principle of designing and constructing external wall structures is that the wall must be airtight and the water vapor permeability of structural layers increases gradually towards the outside surface of the wall. A water vapor barrier may be needed near the inner surface of a wall.
With regard to durability aspects of the wall, driving rain water leakages into wall structures are harmful. Water may enter the wall through connections, construction faults or during unprotected construction work. If the insulation material is foam plastic or other water vapor tight material or if the insulation material is such that can absorb very little moisture, or if there is no ventilation gap behind the façade, water leakages are very risky. Excessive moisture levels may cause mould to develop in the wall. This may be a risk considering also the indoor air quality.
With regard to fire safety, to reach the intended fire safety level for multi-storey buildings, it is recommended to use non-combustible (=A1 or A2-s1, d0 reaction to fire class) or at least B-s1, d0 class external boards/layers. In case of combustible insulation, the boards should be thick enough to protect the insulation.
With regard to structural stability the assessment of the load bearing capacity of the existing walls must include a verification to ensure that it can withstand the mounting of fastening points. Changes in water drainage, changes in humidity and danger of frost heave etc. may affect the structural stability in the long term.
With regard to buildability, the aspects which need to be checked are the needs of space, availability of materials, work force, quality of workmanship. These will depend on the project at hand and on the local conditions.
Recommendations for standardisation bodies
The aim of the project was also to study and summarise relevant standards for sustainable renovations that might need revision and recommendations for standardisation bodies. Relevant standards are in the fields of:
-environmental assessment of building products and buildings,
-life cycle costing,
-service life assessment.
Relevant standards which might need revision
Product level standards
CEN Technical Committee TC 350 has worked out product level environmental declaration standards including product category rules, communication format from business to business use and methodology for the selection and use of generic data in the LCA and EPD use. The standards are: EN 15804, CEN/TR 15941:2010 and EN 15942:2011. Principally these standards are applicable for all building materials and components including refurbishment and renovation materials and components.
Service life assessment
Service life assessment is an important part for life cycle assessment of new buildings. The assessment can be based on the service life planning standard ISO 15686 which includes several parts. These standards are mainly applicable for new buildings. For existing buildings the remaining service life should be estimated on the basis of the inspection of the condition of materials and products by experts. While there are relevant standards for service life predictions for materials and components in general and some material specific standards, there no international standards for assessing the condition of whole buildings. Such a standard should provide a framework for the assessment and reporting building condition in different situations.
The recommendation is to prepare
1)a standard for assessment of building condition,
2)a new service life standard which takes into account the condition of existing building and gives exact instructions for the assessment of remaining service life for building refurbishment.
Life cycle costing
There are international standards and methodologies concerning Life cycle costing. As standardisation mostly concerns terms, process and calculation schemas, the existing standards can be applied both for new construction and renovation. There is no need for any new standards for life cycle costing of refurbishments but the methodological framework for calculating cost-optimal levels of energy performance requirements for new buildings and building elements must be formulated also for extensive energy-intensive renovations.
Euro codes for design
Euro codes are European-wide standardized calculation rules for Building industry. CEN supervised and/or approved those. They have many advantages containing uniform design criteria, harmonizing different national rules and having uniform basis for research & development.
SUSREF project recommends the development of a new Euro code which takes into account refurbishment aspects of building envelope and frame. We recommend the development of a Euro code Design for refurbishment of external walls which describes design methods and performance criteria. Proposal for the content topics are as follows:
-Diagnostics,
-performance criteria according to SUSREF aspects,
-use of different materials (including recycled materials) and their interactions,
-assessment and calculation method for example as in SUSREF Deliverable 2.2
-renovation concepts,
-details for refurbishment (good construction practice),
-execution of work,
-service life design.
CE-marking and product approval
The Construction Product Regulation (CPR) has been adopted by European Commission in 2011 and it replaces Construction Product Directives. The adoption of CPR allows construction products that have been assessed against harmonised standards to be legally placed on the market anywhere in the European Economic Area. Products are fit for their intended use if they comply with a Harmonized Standard, a European Technical Approval or a non-harmonized technical specification recognized at EC level. The CE marking is based on a harmonised product standard (hEN) or a European Technical Approval (ETA). The European Technical Approval granted only by a member body of the European Organisation for the Technical Approvals, EOTA.
European Technical Approval (ETA)
A European Technical Approval (ETA) for a construction product is a technical assessment of its fitness for an intended use. This bases on the contribution made by this product to the fulfillment of the seven Essential Requirements, as stated in the Construction Product Regulation for the construction works in which the product is installed. European Technical approval is the parallel activity for the products which don't have relevant harmonized Standards for showing their conformity for essential requirements.
Recommendations for policy makers
The recast directive on energy performance of buildings forms a strong basis for the regulation and steering of energy performance of existing buildings and building renovations. In July 2012 all Member States should have adopted and published the laws, regulations and administrative provisions necessary to comply with Articles 2 to 18, and with Articles 20 and 27. These include the requirement to take the necessary measures to ensure that when buildings undergo major renovation, the energy performance of the building or the renovated part thereof is upgraded in order to meet minimum energy performance requirements set so far as this is technically, functionally and economically feasible. In addition, the energy performance certificate will include recommendations for the cost-optimal or cost-effective improvement of the energy performance of a building or building unit. The recommendations included in the energy performance certificate shall cover measures carried out in connection with a major renovation of the building envelope.
In addition to the coming legislation and regulations that will be based on the recast energy performance directive, there is also a need to develop other instruments than control and regulatory instruments. Especially fiscal instruments and incentives and informative support will be needed in order to:
-to achieve common willingness among public to make efforts for significantly improved quality and energy performance of exterior walls of buildings
-to avoid risks in the connection of building renovations
-to economically facilitate choices that are excellent from the view point of technical and long-term sustainability reasons.
Especially SUSREF recommends the following measures for steering sustainable refurbishment:
- development and adoption of methods of consultation steering
The development of the ability of planning authorities and building permit authorities to provide more supportive guidance and consultation would facilitate the finding and utilization of refurbishment solutions that are beneficial and advanced from the view point of energy performance and overall sustainability. This is especially important in the current situation where a big number of existing buildings will be renovated and much new information about the sustainable refurbishment concepts of exterior walls is needed. On the other hand, the building authorities considering their role in the process want to avoid a situation where their give guidelines or recommendations about the use of specific solutions. Thus the availability of recognized standards and design guidelines is emphasized.
- reinforcement of informative support and dissemination of information about sustainable refurbishment concepts on national levels
The structure of the building sector is fragmented and there is an extremely large number of actors and large inhomogeneity of actors involved in building processes. Therefore, the information that has been developed on European level about the sustainable refurbishment concepts of exterior walls does not easily reach all actors that would need this information. There is a need to develop the availability of information about refurbishment concepts which are relevant in national context considering the climatic conditions and the quality of the existing building stock. This information should be made available so that designers and other actors would easily access it for example through easy-to-use data bases. However, the reliability of information should be ensured and on the other hand the trust on the good quality of information should be ensured by placing the information on web-pages of recognized local actors that deliver and disseminate guidance for building and construction.
- development of effective incentives for sustainable refurbishment of exterior walls
The implementation of the recast Energy performance directive will ensure the consideration of energy performance when buildings undergo major renovation. The energy performance of the building or the renovated part must be upgraded in order to meet minimum energy performance requirements so far as this is technically, functionally and economically feasible. In order to accelerate needed renovations and to avoid situations where needed renovations are much delayed because of financial reasons, effective incentives are needed. The necessary renovations are often delayed and the selected refurbishment methods are sometimes chosen on the basis of financial reasons that may be short-term and imprudent but on the other hand - important from the view point of the financial capacity of some building owners or tenants. Therefore, rightly directed incentives may considerably promote and speed up renovations that significantly upgrade the energy performance and sustainability of exterior walls.
- promotion of training for improved expertise in design and construction of sustainable refurbishment concepts
Different kinds of measures are needed in order to ensure the dissemination of information to a large group of actors that will need improved knowledge about sustainable refurbishment of exterior walls and sustainable renovation of buildings. The specific consideration of the topic should be ensured both in university and polytechnic schools as well as in training courses provided by associations of designers and by building industry.
- continuous support for demonstration
Different kinds of measures are needed in order to ensure the dissemination of information to a large group of actors that will need improved knowledge about sustainable refurbishment of exterior walls and sustainable renovation of buildings. The specific consideration of the topic should be ensured both in university and polytechnic schools as well as in training courses provided by associations of designers and by building industry.
- citizen engagement
Tenants and building owners living in buildings are the end-users of new technologies for building refurbishment. The increase of public awareness of the importance of sustainable building through information campaigns is also needed. One of the biggest barriers for the quick promotion of sustainable building is the low level of knowledge and awareness in the areas of energy by the end user. Launching information campaigns on new energy saving technologies and renewable technologies (which at the same time fulfill the overall requirements of sustainable building as explained in Section 3.2) might help to overcome the distrust by public on the sustainable refurbishment technologies especially when this happened simultaneously with the provision of effective incentives.
Potential Impact:
SUSREF has developed:
-information about the potential impact of the refurbishment of exterior walls,
-concepts for the refurbishment of exterior walls,
-a systematic approach for the assessment and comparison of concepts
-guidelines for refurbishment processes and for building industry
-recommendations for standardisation bodies and policy makers.
The potential impact of the project will be based on the use and exploitation of these outcomes.
Assessed potential impact of the refurbishment of exterior walls on the European level.
SUSREF aimed at making a realistic assessment about the potential impact of the refurbishment of exterior walls. SUSREF assessed on the bases of calculation that that the total CO2equ saving for the single family houses in Europe is 55.4 Mt and for the multi-story buildings 16.8 Mt per year. Thus in total the assessed saving is 72 Mt during 20112020 per year. This was calculated on the basis of U-value changes and heat degree days by using the proposed refurbishment concepts by the SUSREF partners from different parts of Europe and by using realistic assumptions about the rates of refurbishment.
Business strategies of the SME partners
SMEs have worked out their business strategies. The SMEs created business plans in order to meet the SUSREF goals of dissemination of the R&D results and to take up the results in the businesses of the partners and wider industry delivering either services or producing materials, components or other tangible solutions for sustainable façade refurbishments in various parts of Europe. With a business plan the entrepreneurs analysed the strengths and weaknesses of their own capabilities. The business plan works for a business to look ahead, allocate resources, focus on key points and prepare for challenges and opportunities.
SUSREF has developed knowledge, methods and concepts that can be utilized as expert services offered in the façade structure condition surveys:
-Energy and circumstance simulations
-Life cycle assessment
-Building physics assessment
-Facade renovation services
-Facade renovation designs
Sustainability is one of the main targets in development. Customer, owner and inhabitant want to have a healthy living environment. Because of increasing energy costs our clients need energy efficient buildings. The client needs solutions which take into consideration the technical functionality and economy. The need for the services will be for the whole lifecycle of the building e.g. for the following reasons:
-changes of the owners of the buildings
-changes of the users of the buildings
-changes in legislation
The clients of the project partner Vahanen are house owners, inhabitant associations, property owners, construction companies, developers etc. The clientele varies from country to country. The target market for specialist services will be at the beginning the countries they already are active: i.e. Finland, Estonia, Russia, Romania, UAE and India. EKK assesses that potential exists on the big area of Russia and Ukraine. The other SMEs have domestic or EU market areas.
Vahanen, Repair and EKK also made quantitative assessments about the increase in turnover and workplaces as follows:
The implementation of the systematic approach
The implementation of the systematic approach for the development of new concepts and for the development of expert services will require wide expertise in SMEs. Thus the implementation of the proposed process fits best for enterprises that not very small.
On the basis of the experiences, the systematic approach was found feasible and useful because it supported the product concept developers to:
-iterate and optimize material and structural choices
-compare alternative solutions
-investigate the feasibility of new and innovative solutions
-avoid risks
-assess long-term impacts both from the view point of building performance and environmental and financials impacts
-consider both functionality and process related aspects
-develop systems with help of which clients are supported to set targets for refurbishment works.
Dissemination of results
The main methods and activities with the help of which the outcomes of the project are disseminated are as follows:
-Business strategies and business activities of the SME partners of the project
-With help of the developed business strategies and new business activities, the SMEs of the project will
-adopt new concepts, new processes and new services, and
-disseminate the information about new services and concepts when networking and doing business.
New research foreground of the research institutes and universities
The outcomes of the project will be made use of in on-going and coming research projects and contract projects. For example VTT will utilize and disseminate SUSREF results in the current group of projects Ownership in sustainable building (OKRA) which develops new processes for municipalities and owners when they want to support both professional as well as small builders in sustainable renovation and refurbishment. The aim is to develop for cities processes for consultative steering which encourages builders to adopt sustainable and energy efficient concepts for building renovation.
SUSREF Workshops
The outcomes of the project have been introduced and discussed in workshops in the UK, Spain, Norway and Finland. In all of these workshops a remarkable number of important stakeholders participated, listened to the results and participated to the discussion about how to further disseminate results.
Recommendations
SUSREF has developed guidelines and recommendations for building industry, standardisation bodies and policy makers. The project has not succeeded well in disseminating these recommendations but it is still searching for possibilities and support in dissemination. The recommendations for standardisation bodies have been given to the representative of the Confederation of Finnish Construction Industries and its president for building regulations and standardisation to be further promoted in international networks and organizations.
Teaching and education
The results from the SUSREF project are being presented to students in Cardiff University engaged in postgraduate studies at Masters and PhD level in the general areas of building and sustainability. Cardiff University is currently developing plans for a Masters in Building Conservation which will incorporate findings from SUSREF research as a major component.
Training courses
The research organizations VTT, TECNALIA, BRE and SINTEF and their staff often participate as lecturers in different kinds of training courses. The researchers will utilize the project material and disseminate results in coming events which train professionals in sustainable renovation and refurbishment. Because of the importance of the matter, these events will be many during the coming years.
Scientific articles
The project researchers have written manuscripts for scientific articles and conference papers. This is the best route to disseminate the results for the research community. Existing article and papers for refereed journals and conferences are as follows:
Tarja Hakkinen, Systematic method for the sustainability analysis of refurbishment concepts of exterior walls, Manuscript submitted to Construction and Building Materials, Reviewed and preliminary accepted with a request for few changes, Changes made and manuscript resubmitted.
Abstract: Because of the age of the European building stock and because of the new energy performance regulations, safe and efficient concepts have to be developed for the refurbishment of exterior walls. The objective of this paper is to explain the method that was developed in the European SUSREF project for the analysis of refurbishment concepts, and describe how the method was effectively implemented during the project. Both generic refurbishment concepts and company specific solutions were developed for the refurbishment of building external walls. All concepts were systematically assessed with help of the method. The method includes a list of performance criteria and detailed guidelines for the assessment. Important aspects include not only the aspects of technical and functional performance but also process related aspects and life cycle aspects. The process related aspects should not be limited to technical feasibility but also consider the impacts caused to neighboring buildings and their users. Life cycle aspects should cover both environmental as well as financial aspects. The approach was tested during the project and it was found suitable both for the development of new innovative solutions as well as for the improvement of more conventional solutions. The approach is also recommended to be made use of in the development of design codes for refurbishment concepts of exterior walls. A systematic method should also be used in the dissemination of information about recommended refurbishment concepts for designers.
Tomi Toratti et al. Durability considerations of refurbished external walls. A manuscript to be be submitted to Construction and Building Materials.
Abstract: This paper draws attention to some of the main findings and results of the European project: Sustainable Refurbishment of Building Facades and External Walls. The material presented includes only some analyses cases which were carried out during the project. This topic has a have high industrial relevance and the results may be, to a large extent, utilised as recommendations for refurbishment projects.
In planning of a refurbishment, there is no point to try to prolong the service life of the original concrete core if the limit state of the service life has already been reached at the time of refurbishment. The extending of service life is only reasonable by a coating if the carbonation has not reached the depth of reinforcement.
Erkki Vesikari R.M. Ferreira. Simulation technique for service life assessment of façade refurbishment. A paper submitted to IALCCE conference. Third International Symposiun on Life-Cycle Civil Engineering. October 3 - 6.2012. Vienna Austria
ABSTRACT: The EU Research Project SUSREF proposes as its outcome sustainable concepts and technologies for the refurbishment of building facades and external walls. One of the tasks in the SUSREF project was to predict the performance and service life of the proposed refurbishment concepts.
Erkki Vesikari and R.M.Ferreira. Service Life Assessment for refurbishment concepts of concrete façades. fib Symposium: Concrete Structures for Sustainable Community STOCKHOLM 2012 11-14 June 2012 Royal Institute of Technology (KTH) Stockholm, Sweden
Abstract: The EU Research Project SUSREF proposes new sustainable concepts and technologies for the refurbishment of building facades and external walls. As one part of the project it was necessary to identify the volumes of needs of refurbishment in the EU and in neighboring areas and to evaluate the meaning of this in terms of environmental and economic impact and business potential. Within the tasks of the SUSREF project was also the service life assessment of the proposed refurbishment concepts of building facades and external walls. A simulation software, developed at the Technical Research Centre of Finland, was used to assess the performance and possible durability risks of the refurbishment concepts. The simulation software is able to emulate the temperature and moisture variations in a cross-section of the wall and to apply temperature and moisture sensitive degradation models at critical points of the structure. The software was applied for analyses of the refurbishment concepts in several European climates and with various material options. In this paper some results of the analyses are presented.
SUSREF Publications
The main results of the project are also reported in three publications which are available on the VTT web site:
http://www.vtt.fi/publications/?lang=en
The VTT publications register is available also via WWS, the worldwide portal of science and research publications.
The final reports of the project are as follows:
-Sustainable refurbishment of exterior walls and building facades. Final report Part A. VTT Technology 30. Espoo 2012
-Sustainable refurbishment of exterior walls and building facades. Final report Part B. VTT Technology 33. Espoo 2012
-Sustainable refurbishment of exterior walls and building facades. Final report Part C. VTT Technology 36. Espoo 2012
SUSREF web page
The project has a web page where all SUSREF deliverable are available. VTT will maintain the page and offer all project research outcomes for use for related coming research projects.
http://cic.vtt.fi/susref/
List of Websites:
http://cic.vtt.fi/susref/
Coordinator Dr Tarja HAkkinen e-mail: tarja.hakkinen (at) vtt.fi
SUSREF developed technologies and methodologies for sustainable refurbishment of external walls. SUSREF was based on the premise that:
1) refurbishment of external walls is one of the most efficient ways of reducing environmental impacts of European building stock;
2) European building sector is facing huge needs of renovation; refurbishment of external walls is among the most urgent tasks;
3) Although there are technological solutions, the risks and optimal solutions are not fully understood;
4) External walls have an extensive effect on building performance and several aspects have to be taken into account when developing new concepts.
5) Urgent needs of refurbishment are not only faced in the EU but also in neighboring areas; development of functional and environmentally efficient technologies would support the European industry to export projects and the neighboring areas to adopt sustainable technologies.
The objective of the project was to:
1) identify the needs to refurbish building envelops in the EU to understand the significance in terms of environmental and economic impacts;
2) develop a systemized method to manage the functional performance of solutions;
3) develop sustainable product concepts;
4) disseminate results for building industry, standardisation bodies, and policy-makers in terms of technological knowledge, guidelines and recommendations.
SUSREF assessed the potential savings in energy and costs with help of using scenarios for the refurbishment of external walls. The total investment cost was assessed to be 28000 million euro/year directed for the energy related refurbishment. On the other hand the savings in energy costs were assessed to be 2500 million euro/year. The difference in annual Life Cycle Cost is in average -11 000 million euro within 20 years. In addition, it was assessed that the corresponding increase of labor would be 396000 man years/year. The estimated potential CO2 savings is 72 Mt/y.
It was defined that the overall sustainability of the developed concepts and technological solutions of the project has to be assessed considering the following aspects:
1) Durability,
2) Impact on energy demand for heating,
3) Impact on energy demand for cooling,
4) Impact on renewable energy use potential,
5) Impact on daylight,
6) Environmental impact of manufacture and maintenance,
7) Indoor air quality and acoustics,
8) Structural stability,
9) Fire safety,
10) Aesthetic quality,
11) Effect on cultural heritage,
12) Life cycle costs,
13) Need for care and maintenance,
14) Disturbance to the tenants and to the site,
15) Buildability.
Project Context and Objectives:
The starting point of the SUSREF project was as follows:
1) The Refurbishment of the external walls of any building is one of the most efficient ways of improving the environmental impacts of the European building stock.
2) The age of the build structure in the European building stock is causing a situation where the building sector and building owners are facing the extensive challenge of refurbishing many of the buildings. The renovation and refurbishment of the building facades and external walls are among the most urgent tasks to be undertaken.
3) Although there are technological solutions for refurbishment of external walls, the risks and optimal solutions of the new concepts are not fully understood. In order to avoid creating early problems in the energy renovation of buildings, the new concepts and solutions cannot be used without achieving a comprehensive understanding about the building/s physical behaviour, the products and the optimal solutions with regard to energy efficiency and environmental impacts.
4) External walls have an extensive effect on building performance and several aspects have to be taken into account when developing new concepts for refurbishment. An optimal approach should consider the following aspects: a) effect on energy consumption, b) building physical behaviour and durability, c) good integration with building structure, details and building services, d) effect on indoor environment and comfort, e) aesthetics.
5) The urgent need of good building refurbishment methods are not only faced in the EU but also - even more greatly - in neighboring areas and other parts of the world. The development of functional and environmentally efficient technologies and concepts would support the European industry in exporting technology and projects, and to support and advise the neighboring areas to adopt more sustainable technologies.
This project aimed at creating the following outputs:
- inform building industry about the optimal sustainable technologies available and potential of these technologies
- guide and inform standardisation bodies about the comprehensive sustainability performance of building external walls, giving recommendations on how this should be considered in the further development of CPD related product specifications and sustainable building standardisation
- inform policy makers about the overall significance of building external walls in the progression of the European building stock towards sustainable performance.
The main objectives of the SUSREF project were:
1) to identify and understand the volume of need to refurbish the building envelops in the EU and in neighboring areas. To understand the meaning of these needs in the first place in terms of environmental impacts and secondly in terms of economic impact and business potential;
2) to develop a systemized theory and differing technologies when refurbishing building facades and external walls in order to ensure the functional excellence of solutions. To analyse technologies from the view point of building physics, comfort and energy efficiency. To consider the various challenges in different parts of Europe in terms of present climate and foreseen risks of changes, technological differences, and cultural-historic differences. And finally to deliver sets of relevant performance specifications for sustainable refurbishment;
3) to develop systemized methods for consideration of environmental performance of external walls. To assess and ensure the sustainability of the developed technologies in terms of environmental impacts, life cycle costs, social and cultural impacts;
4) to develop sustainable concepts for carrying out refurbishments projects;
5) to disseminate the results for a) building industry, b) standardisation bodies, and c) policy-makers and authorities in terms of technological knowledge, guidelines and recommendations.
The existing methodologies and knowledge on which the project was based include the following:
1) Modeling of solutions for the refurbishment of façades and external walls
2) Technological solutions developed for the refurbishment of facades
3) Life cycle assessment methods
4) Knowledge management methods and tools for optimisation
5) Building physical and energy models
There have been attempts to model refurbishment solutions. The project made use of these existing models and further develop those in order to better suit for the wider comprehensive target of the project. The project made use of the existing and advanced technological solutions, and analysed, modeled, improved and developed concepts so that selection can be done considering the regional and localised climatic conditions, ensuring good functionality and optimising the energy and environmental efficiency.
LCA is a technique for assessing the environmental aspects and potential impacts with a product by compiling an inventory of relevant inputs and outputs of a product system, evaluating the potential environmental impacts associated with those inputs and outputs and interpreting the results of the inventory analysis and impact assessment phases in relation to the objectives of the study. General guidelines are given in ISO standards 14040 and 14044 and in the International Life Cycle System Handbook. Rules for the environmental declaration of building products are given in ISO 21930. Life cycle costing (LCC) is a technique for estimating the cost of whole buildings, systems and/or building components and materials, and for monitoring the occurred cots and impacts throughout the building life. The technique can assist decision-making in building investment projects. LCC is used to evaluate the cost performance of a building throughout its lifecycle, including acquisition, development, operation, management, repair, disposal, and decommissioning. In addition to internationally agreed standards and guidelines, there are a number of national and specific methodologies for integrated life-cycle management of buildings. SUSREF applied the existing life cycle assessment methods for the assessment of refurbishment concepts.
Building physical models have been developed for the analysis and assessment of building physical behavior and energy performance. These are assessment and simulation models that cover moisture dynamics in building envelopes, computational simulation of heat, air and moisture transport in materials and constructions and the hygrothermal interaction between the materials of building envelope and surrounding climate. These models enable assessment of a layout in respect to e.g. effects on indoor air, moisture buffering, air flow patterns near surface and risk of mould growth. Some of the tools concentrate on single building components, as building envelope (MATCH), and others on the whole building performance (WUFI+). Many of the common models, however, concern only heat transfer problems and are multidimensional tools for analysing thermal bridges (HEAT2). Also on the building level, the simulation of energy performance is dominating (EnergyPlus). The purpose of these models is to support the achievement of energy efficient and durable constructions and good indoor air quality.
The aim of the project was also to study and summarise relevant standards for sustainable renovations that might need revision and recommendations for standardisation bodies. Relevant standards are in the fields of:
- environmental assessment of building products and buildings,
- life cycle costing,
- service life assessment.
The CE marking is based on a harmonised product standard (hEN) or a European Technical Approval (ETA). The European Technical Approval granted only by a member body of the European Organisation for the Technical Approvals, EOTA. The building materials which used in renovation and refurbishment are CE-marked now according to the same rules as the products used in new constructions. For the harmonized standards to be relevant for refurbishment work, it would be necessary that the intended use of the product includes refurbishment and that all relevant material properties are declared.
The product-related requirements are described in the relevant technical product standard and for renovation and refurbishment products there are no individual separate technical standards exists. Products used in renovation and refurbishment should fulfill the same requirements that products used in new construction. On the other hand new materials and product concepts will be developed with new properties for the renovation and refurbishment market. New, technical standards and test methods may be necessary to accommodate to these new products. For these cases the building material industry needs to take the standardization initiative towards to the members of CEN committee who then launches the preparation work for new standard. The process for new standards already exists and even this is quite long lasting procedure there is no need for new working method (standard procedure) for renovation materials use.
In the transformation of buildings to sustainability, governmental authorities may play different roles:
- As a governor through the launch of control and regulatory instruments.
- As developer including green procurement specifications in housing developments and public buildings.
- Acting as a demonstrator or "early adopter" of new solutions demonstrating the validity and viability of new solutions in pilot buildings or their own property buildings
- Acting as a mobilizer of the sector, promoting the implementation of concepts or solutions through economic and market based instruments rewarding, incentivizing, and introducing direct subsidies.
In addition to the coming legislation and regulations that will be based on the recast energy performance directive, there is also a need to develop other instruments than control and regulatory instruments. Especially fiscal instruments and incentives and informative support will be needed in order to:
- to achieve common willingness among public to make efforts for significantly improved quality and energy performance of exterior walls of buildings
- to avoid risks in the connection of building renovations
- to economically facilitate choices that are excellent from the view point of technical and long-term sustainability reasons.
Project Results:
Main S&T results
SUSREF developed
- information about the significance of the refurbishment of exterior walls of the European building stock. The significance was assessed in terms of potential energy savings, CO2 savings, life cycle costs and labor.
- a systemized approach for the assessment and development of refurbishment concepts for exterior walls. This approach includes assessment criteria and detailed guidelines for assessment methods.
- general and specific refurbishment concepts and their assessment results
- guidelines for refurbishment projects and building industry
- recommendations for standardisation bodies and policy makers.
Significance of the refurbishment of exterior walls
The total wall areas of the European residential building stock were summarised based on earlier research data (IMPRO 2008). The estimated façade areas are 12600 million m2 for single family houses and 4450 million m2 for multifamily and high rise buildings. The potential of the refurbishment of exterior walls was assessed in terms of estimated savings in energy use, GHG emissions, life cycle costs and labor.
The assumed maximal potential of SUSREF concepts in Europe was as follows:
-Adding new/more insulation will be relevant for 4060% of the building stock during 10 years depending on building age and climate zone
-Stone walls are not usually be insulated outside but in the case of an extensive renovation.
-Demolition of 5% of the present building stock will take place during the next 10 years.
-Increase of 7% of present building stock will take place during the next 10 years.
The walls already insulated or replaced by new ones have not been included to the volumes of potential refurbishments. Some energy saving actions will be done also for those during the next 10 years but the relative importance of those actions is small.
For a certain number of buildings there are either no possibilities or needs to make external changes (25-50% of the building stock built before 1945 (because of aesthetic and cultural reasons) and 20-40% of the building stock built after 1970 (because the walls are in good condition).
When calculating walls to be refurbished life-cycle optimized comprehensive concept was preferred instead of separate actions.
The assessed volumes of refurbishment are bigger than what has been the case during the last 10 years. The explanation for this choice is that it was thought that the different new steering mechanisms will accelerate the building refurbishment projects. The project assessed the potential effects of the refurbishment of exterior walls in terms of GHG emissions, costs and labor. The result was assessed with the help of the description of refurbishment concepts and scenarios for the realization of refurbishments. The total investment cost was assessed to be 28000 million euro/year directed for the energy related refurbishment. The savings in energy costs were assessed to be 2500 million euro/year. The difference in annual Life Cycle Cost is in average -11 000 million euro within 20 years. In addition, it was assessed that the corresponding increase of labor would be 396000 man years/year. The estimated GHG saving was 72 Mt/y.
Systematic approach for the assessment of refurbishment concepts
The following list shows the final sustainability assessment criteria defined by the SUSREF project. These criteria together with the related assessment methods define the systematic approach for the sustainability assessment of refurbishment concepts of exterior walls. On the basis of the discussion it was defined that the overall sustainability of the developed concepts and technological solutions of the project will be assessed considering the following 15 aspects:
-Durability
-Impact on energy demand for heating
-Impact on energy demand for cooling
-Impact on renewable energy use potential
-Impact on daylight
-Environmental impact of manufacture and maintenance
-Indoor air quality and acoustics
-Structural stability
-Fire safety
-Aesthetic quality
-Effect on cultural heritage
-Life cycle costs
-Need for care and maintenance
-Disturbance to the tenants and to the site
-Buildability
Although the importance of different aspects vary with practical circumstances and with the desires and requirements of clients, the consideration of all aspects is important. Some of the aspects should be studied quantitatively in order to give an adequate understanding about the impacts. These aspects are Durability, Impact on energy demand, Environmental impact and Life Cycle costs. The list also covers important aspects related to construction and operational processes (Disturbance, Buildability and Need for care and maintenance). The list covers the most important functional performance aspects of exterior walls (Structural stability, Fire safety, Aesthetic quality, impact on Indoor environment). The usability of the approach requires the definition of assessment methods for different aspects. The recommended assessment methods are carefully described in SUSREF deliverables. The defined methods for durability, energy performance, environmental impacts and life cycle costs are simulation and calculation methods.
According to SUSREF conclusions the building physical development process can be seen as an iteration process where the best solution for any actual case is found by optimizing:
1) thermal performance of the envelope: reduction of the heat losses through the envelope, minimising thermal bridges,
2) moisture performance of the envelope: ensuring drying capacity, avoiding condensation,
3) durability of the constructions: reduction of the risk for mould, decay, frost and corrosion,
4) indoor air quality and comfort: thermal symmetry, no draft, control of humidity.
Dynamic simulations with hygrothermal simulation tools are an important part of the assessment work. Depending on the construction type and refurbishment method to be analysed, the most suitable calculation and simulation tools should be chosen. One-dimensional (1D) coupled heat and moisture calculations tools are the best choice for constructions and solutions consisting of just homogenous layers. Ventilated cavities can be studied simplified with these tools, too. Two-dimensional (2D) coupled heat and moisture calculations tools should be used for constructions containing inhomogeneous layers, e.g. stone walls, fastenings, and ventilation cavities. Generally, 1D-tools are sufficient for most of the analysis with skilled expert use. The computation of coupled heat and moisture transport in two dimensions is usually time-consuming and the detailed information from a 2D or even 3D calculation may be overruled by other uncertainties.
General refurbishment concepts
SUSREF developed both general and specific refurbishment concepts for exterior walls. The study combined different refurbishment technologies into four main groups. The technologies differ from each other mainly by the manner in how placement of new insulation layers would be normally undertaken. The primary technologies for refurbishing external wall are:
-Technologies for replacing existing walls (R)
-Technologies for applying external (insulation) layers (E)
-Technologies for inserting (insulation) materials in cavities in existing walls (C)
-Technologies for applying internal insulation (I).
The overall results are presented in Deliverable D4.2 and in SUSREF Final report Par B General refurbishment concepts. The concepts were assessed from the view point of the selected 15 criteria as explained in the section Systematic approach for the assessment of refurbishment concepts. The following buildings types are covered in the development and assessment of the generic concepts:
-Small houses
-Terraced houses
-Multi-storey Apartments/Flats.
The original wall types considered in the assessment of the generic refurbishment concepts are as follows:
-Solid wall (brick, natural stone)
-Sandwich element (concrete panel + concrete panel)
-Load bearing wood structure (wooden frame)
-Insulated load bearing cavity (concrete block + concrete block)
-Load bearing cavity without insulation (brick + concrete block)
-Load bearing wood structure (wooden frame)
-Non-load bearing cavity (hollow brick + perforated brick)
-Non-load bearing concrete block without insulation (hollow brick + concrete block).
The generic concepts were assessed analytically and when relevant, using a parametric approach. This means that each performance aspect of the generic concepts will be assessed by dealing with relevant issues as parameters. Relevant issues are very much determined by specific performance aspects, and these could be different in many issues. Relevant issues may be for example be Quality and performance properties of materials, Thickness of insulation and other layers, Existence of air cavity, Fixing mechanisms, Quality of surface material, Condition of the existing structure, and Rainfalls and temperatures.
Building physical assessment and Durability
The main principle of designing and constructing wall structures is that the wall must be airtight and the water vapor permeability of structural layers increases gradually towards the outside surface of a wall. A water vapor barrier may be needed near the inner surface of a wall, if the water vapor permeability of materials is too high and the materials can't absorb all the extra moisture or the moisture levels inside the wall may become too high. Rain water leakages into wall structures through defected joints and construction faults are harmful. If the insulation material is foam plastic or other water vapor tight material or if the insulation material is such that can absorb very little moisture, water leakages are especially harmful. The leaked water causes the biggest problems with mineral wool insulated timber frame walls. Excessive moisture levels may cause mould or rotting of timber parts.
There are some principals that help the design for good durability:
-ensure that walls and their joints are airtight and the water vapor permeability of structural layers increases gradually towards the outside surface of a wall
-it is more effective to add retrofit insulation on the outer surface of a wall and the risks of moisture condensation and accumulation in the existing wall are lower
-the thicker retrofit insulation on the exterior surface of a wall the better
-the thicker retrofit insulation on the inner surface of a wall the worse
-use materials and structures that are known to be durable
-ensure, that the old wall can hold the extra weight of retrofit part and if not, add extra bindings and fixings to the old wall
-design the structure and it's joints, sealings and supports carefully
-prevent driven rain water to flow into a wall structure and especially to the warmer side of a cellular plastic thermal insulation
-ensure the water tightness of joints between window, wall and external window sill
-control manufacturing and installation
-make inspections periodically
-repair found defects in time
Different refurbishment concepts of building facades and external walls were analysed for possible long-term degradation. The analyses were conducted for the climate conditions of various European climates and with various outer core materials and thermal insulations. Degradation models used were as follows:
Frost attack
VTT simulation software assesses the occurrence and propagation of frost damage is evaluated based on the theory of critical degree of saturation developed by [Goran Fagerlund 1977]. Frost damage is assumed to take place when the moisture content of concrete exceeds the critical water saturation and the temperature descends below the freezing point at the same time.
Carbonation and corrosion
The model used to evaluate the rate of corrosion on the reinforcement includes an initiation period and a propagation period. Initiation of corrosion is assumed to take place when carbonation reaches the depth of reinforcement. Both the rate of carbonation and the rate of corrosion depend on the temperature and moisture content of concrete.
Mould growth
Numerical simulation of mould growth can be used as one of the hygrothermal performance criteria for the building structures. Mould is one of the first signs of too high moisture content of materials and it may affect the indoor air quality and also the appearance of the visible surfaces. Mould growth potential can be predicted by solving a numerical value, mould growth index, by using the dynamic temperature and relative humidity histories of the subjected material surfaces. The model was originally based on mould growth on wooden materials but has now been completed with several other building materials. The model can be used parallel with heat, air and moisture simulation models or as a post-processing tool.
Environmental impact
Environmental impact assessment focuses on the impact of non-renewable energy (energy transmission through the wall and energy consumption of refurbishment materials), non-renewable raw materials (from energy production and refurbishment materials) and especially released greenhouse gases and thus carbon footprint. Main parameters which were used for the assessment of environmental impact and for different wall renovation concepts were:
-Material type (insulation, façade) and properties (specific weight, consumption, thermal conductivity, environmental impact)
-Existing wall type, deterioration rate and corresponding U-value
-Renovation concept and target U-value
-Building location and heating degree days
-Heating type and environmental impact from heating
-Material service lives and need for maintenance.
Environmental impact in the connection of building renovations depends on the existing building type, building condition and renovation concept used. In typical building design, where the shape of building is square and rectangular, the exterior walls form 1.2 - 1.5 wall-m2/one floor-m2. Wall structures can be divided to light, medium and massive structures and when the used material amount is high, normally also environmental impact are higher compared to lightweight cases. The same principle is applicable also to renovation concepts; the lighter the structure is typically the smaller are the environmental impacts of the concept. At the same time, exterior walls are responsible for the heat transmission and thus have an effect to the total energy performance. Because of that, the impact from renovation materials should be studied alongside with the heat transmission and heating type. Depending on the existing building types, the additional insulation can be placed to the existing wall either externally, internally or into the wall cavity. This study focused mainly on the external and internal renovation cases because the material consumption remains small in the case of cavity walls and doesn't cause so significant effect in terms of energy saving and environmental impact. However, cavity walls are included when the renovation is performed internally or externally. The examples are given for chosen building types to illustrate the ability of energy saving building renovation and environmental impact.
In the case of external renovation, where façade is installed with the presence of air gap, different new façade materials can be used. Façade types studied in this survey were concrete, wood and clay brick façades.
The best façade material in terms of environmental impacts (carbon footprint, non-renewable raw material and - energy consumption), was wooden façade. This renovation concept is a light weight option, wood is a renewable raw material and timber production utilizes by-product energy which also renewable.
In the regions where heating period is long (Northern Europe), the materials used in wall renovation can cause up to 40% of total carbon footprint (20 year operation). This result refers to a case where mineral wool with 3-layer rendering façade was used and heating energy was produced with the Nordel electricity mix (where renewable energy share is high).
For the U-value 0.21 W/m2K, the materials share from total CF is roughly 10 - 15% but it varies depending on heating types. In the case of U-value 0.1 it is varies between roughly 30-40%. The material share can be higher, when high share of heating energy is produced from renewable resources.
Present study shows that exterior wall renovation can achieve big reduction in energy saving measures and environmental impact. Which renovation option is suitable and best in particular cases should be determined considering the overall building condition, historical background and building neighborhood and region. Walls form only one part of the buildings and impacts should be assessed also on building level.
Life cycle costing
The Life Cycle costing covers only extra costs and energy cost caused by refurbishment. The analysis includes price of money (+ 2%/y). Economic assessment is based on the calculation of life cycle cost according to ISO 15686-5. The results are presented in terms of net present values. This is calculated by summing up the activated costs in different years for present with present unit costs (without discount rate). The energy costs were calculated considering the realistic increase of costs. The present value methodology means summing up of the activated costs in different years for present either with present unit costs or taking the foreseen realized costs (usually energy cost) into account.
The refurbishment concepts were compared to a basic case in order to understand more clearly the different effect of material and structure selections. The results show that it is not profitable to improve the thermal insulation of an external wall if the outer layer of the wall doesn't need repair. If the energy price increase rate is high, the refurbishment may become profitable.
Specific refurbishment concepts
The 6 SME partners of the project improved and developed concepts for the refurbishment of exterior walls. The work focused on the chosen common walls types, building types and refurbishment technologies. The research organisations and universities of the project carried out assessments in accordance with the chosen approach.
Altogether 16 refurbishment concepts were developed. The refurbishment concepts developed by the SMEs are listed in the following:
1 Brick wall with ventilation gap and vacuum insulated panel
2 Re-SOLAR (structural solutions collect solar energy and both retain it for the heating and protect the building from overheating)
3 ETICS applied to sandwich element
4 ETICS (External thermal insulation composite systems) applied to sandwich element internal layer
5 ETICS applied to insulated panel RUS (RUS refers to possible areas of application)
6 ETICS applied to solid panel RUS
7 Filling brick wall cavities with carbamide resin foam
8 Thermo-reflective multi-foil outer insulation of brick wall with controllable ventilation air gap before insulation
9 Exterior refurbishment of wooden frame walls with a flex system board insulation
10 Transparent insulation
11 External insulation of solid rubble stone wall with vapor-open natural insulation material and ventilated timber cladding
12 External insulation of solid rubble stone wall with semi-vapor-open mineral wool insulation material and acrylic render
13 External insulation of solid rubble stone wall with expanded polystyrene insulation material and acrylic render
14 External shelter of solid rubble stone wall with unventilated dark-colored steel sheet cladding
15 Internal insulation vapour-open of solid rubble stone wall with lime-sand pointing outside
16 Load bearing ventilated façade
The following information was developed for all concepts.
-cross section figures of the existing wall
-cross section figures of the refurbishment solution
-material layers and thicknesses
-working methods
-areas of suitable application
-known problems related to refurbishment method
-market potential.
Usability of the systematic approach
The starting point of the project was that a systematic approach is needed especially for SMEs when they start to improve refurbishment concepts and develop new concepts. The systematic approach was found feasible and useful because it supported the product concept developers to:
-iterate and optimize material and structural choices
-compare alternative solutions
-investigate the feasibility of new and innovative solutions
-avoid risks
-assess long-term impacts both from the view point of building performance and environmental and financials impacts
-consider both functionality and process related aspects
-develop systems with help of which clients are supported to set targets for refurbishment works.
Tools for decision making sustainable refurbishment of outdoor walls
The main objective in developing the tool was to provide an efficient and effective tool for the practitioner, such as the architects, designers and building contractors, in order to identify alternatives for technical solutions for sustainable refurbishment. The developed tool offers quick access to a number of refurbishment solutions studied in the project and leads to detailed information about how suitable and buildable the solutions are. The criteria included in the tool are: Durability, Care and maintenance, Indoor climate, Heating energy, Cooling energy, Renewables, Environment, LCC, Aesthetic quality, Cultural heritage, Structural stability, Fire safety, Buildability, Disturbance, Daylight . Qualitative scales for each of the 15 criteria were prepared and linked to the first level of the tool. See the following table. The table shows an example of a qualitative scale for retrofitting insulation regarding maintenance needs and vulnerability to damage.
Sets of performance specifications
SUSREF project developed concepts for the refurbishment of exterior walls. The project developed both generic concepts as well as specific concepts. The specific concepts were developed considering specific buildings markets and geographical conditions. The specific concepts are introduced with help of the tool SUSREF SPECIFICATIONS. This document presents the contents and the operating principles of the tool:
Outline of concepts
Guidelines for building industry
Mainly on the basis of Task 4.2 outcomes, the project developed guidelines for building industry. The guidelines are presented in Deliverable 7.4 and in SUSRE Final report Part A. The short summary of the guidelines is as follows:
The focus of the work was to pay attention to some of the main findings and results of the previous more thorough technical analysis reports on the refurbishment concepts. The material presented includes summaries and conclusions of several analyses. Only the main results of some topics are given here, the background analysis may be found from the technical reports (mainly report D4.2). These topics have high industrial relevance and the results may be, to a large extent, utilised as recommendations for refurbishment projects. The use of the SUSREF approach is recommended, this approach relates to the following aspects: Durability, need for care and maintenance, indoor air quality, acoustics + thermal comfort, impact on energy demand for heating and cooling, impact on renewable energy use potential, environmental impact of manufacture and maintenance, life cycle costs, aesthetic quality, effect on cultural heritage, structural stability, fire safety, buildability, disturbance to the tenants and to the site and impact on daylight.
As guidelines to the industry when developing concepts for the refurbishment of external walls, the following recommendations are given.
The building physical performance of the wall has to be checked with suitable methods (as given in D2.2). The main principle of designing and constructing external wall structures is that the wall must be airtight and the water vapor permeability of structural layers increases gradually towards the outside surface of the wall. A water vapor barrier may be needed near the inner surface of a wall.
With regard to durability aspects of the wall, driving rain water leakages into wall structures are harmful. Water may enter the wall through connections, construction faults or during unprotected construction work. If the insulation material is foam plastic or other water vapor tight material or if the insulation material is such that can absorb very little moisture, or if there is no ventilation gap behind the façade, water leakages are very risky. Excessive moisture levels may cause mould to develop in the wall. This may be a risk considering also the indoor air quality.
With regard to fire safety, to reach the intended fire safety level for multi-storey buildings, it is recommended to use non-combustible (=A1 or A2-s1, d0 reaction to fire class) or at least B-s1, d0 class external boards/layers. In case of combustible insulation, the boards should be thick enough to protect the insulation.
With regard to structural stability the assessment of the load bearing capacity of the existing walls must include a verification to ensure that it can withstand the mounting of fastening points. Changes in water drainage, changes in humidity and danger of frost heave etc. may affect the structural stability in the long term.
With regard to buildability, the aspects which need to be checked are the needs of space, availability of materials, work force, quality of workmanship. These will depend on the project at hand and on the local conditions.
Recommendations for standardisation bodies
The aim of the project was also to study and summarise relevant standards for sustainable renovations that might need revision and recommendations for standardisation bodies. Relevant standards are in the fields of:
-environmental assessment of building products and buildings,
-life cycle costing,
-service life assessment.
Relevant standards which might need revision
Product level standards
CEN Technical Committee TC 350 has worked out product level environmental declaration standards including product category rules, communication format from business to business use and methodology for the selection and use of generic data in the LCA and EPD use. The standards are: EN 15804, CEN/TR 15941:2010 and EN 15942:2011. Principally these standards are applicable for all building materials and components including refurbishment and renovation materials and components.
Service life assessment
Service life assessment is an important part for life cycle assessment of new buildings. The assessment can be based on the service life planning standard ISO 15686 which includes several parts. These standards are mainly applicable for new buildings. For existing buildings the remaining service life should be estimated on the basis of the inspection of the condition of materials and products by experts. While there are relevant standards for service life predictions for materials and components in general and some material specific standards, there no international standards for assessing the condition of whole buildings. Such a standard should provide a framework for the assessment and reporting building condition in different situations.
The recommendation is to prepare
1)a standard for assessment of building condition,
2)a new service life standard which takes into account the condition of existing building and gives exact instructions for the assessment of remaining service life for building refurbishment.
Life cycle costing
There are international standards and methodologies concerning Life cycle costing. As standardisation mostly concerns terms, process and calculation schemas, the existing standards can be applied both for new construction and renovation. There is no need for any new standards for life cycle costing of refurbishments but the methodological framework for calculating cost-optimal levels of energy performance requirements for new buildings and building elements must be formulated also for extensive energy-intensive renovations.
Euro codes for design
Euro codes are European-wide standardized calculation rules for Building industry. CEN supervised and/or approved those. They have many advantages containing uniform design criteria, harmonizing different national rules and having uniform basis for research & development.
SUSREF project recommends the development of a new Euro code which takes into account refurbishment aspects of building envelope and frame. We recommend the development of a Euro code Design for refurbishment of external walls which describes design methods and performance criteria. Proposal for the content topics are as follows:
-Diagnostics,
-performance criteria according to SUSREF aspects,
-use of different materials (including recycled materials) and their interactions,
-assessment and calculation method for example as in SUSREF Deliverable 2.2
-renovation concepts,
-details for refurbishment (good construction practice),
-execution of work,
-service life design.
CE-marking and product approval
The Construction Product Regulation (CPR) has been adopted by European Commission in 2011 and it replaces Construction Product Directives. The adoption of CPR allows construction products that have been assessed against harmonised standards to be legally placed on the market anywhere in the European Economic Area. Products are fit for their intended use if they comply with a Harmonized Standard, a European Technical Approval or a non-harmonized technical specification recognized at EC level. The CE marking is based on a harmonised product standard (hEN) or a European Technical Approval (ETA). The European Technical Approval granted only by a member body of the European Organisation for the Technical Approvals, EOTA.
European Technical Approval (ETA)
A European Technical Approval (ETA) for a construction product is a technical assessment of its fitness for an intended use. This bases on the contribution made by this product to the fulfillment of the seven Essential Requirements, as stated in the Construction Product Regulation for the construction works in which the product is installed. European Technical approval is the parallel activity for the products which don't have relevant harmonized Standards for showing their conformity for essential requirements.
Recommendations for policy makers
The recast directive on energy performance of buildings forms a strong basis for the regulation and steering of energy performance of existing buildings and building renovations. In July 2012 all Member States should have adopted and published the laws, regulations and administrative provisions necessary to comply with Articles 2 to 18, and with Articles 20 and 27. These include the requirement to take the necessary measures to ensure that when buildings undergo major renovation, the energy performance of the building or the renovated part thereof is upgraded in order to meet minimum energy performance requirements set so far as this is technically, functionally and economically feasible. In addition, the energy performance certificate will include recommendations for the cost-optimal or cost-effective improvement of the energy performance of a building or building unit. The recommendations included in the energy performance certificate shall cover measures carried out in connection with a major renovation of the building envelope.
In addition to the coming legislation and regulations that will be based on the recast energy performance directive, there is also a need to develop other instruments than control and regulatory instruments. Especially fiscal instruments and incentives and informative support will be needed in order to:
-to achieve common willingness among public to make efforts for significantly improved quality and energy performance of exterior walls of buildings
-to avoid risks in the connection of building renovations
-to economically facilitate choices that are excellent from the view point of technical and long-term sustainability reasons.
Especially SUSREF recommends the following measures for steering sustainable refurbishment:
- development and adoption of methods of consultation steering
The development of the ability of planning authorities and building permit authorities to provide more supportive guidance and consultation would facilitate the finding and utilization of refurbishment solutions that are beneficial and advanced from the view point of energy performance and overall sustainability. This is especially important in the current situation where a big number of existing buildings will be renovated and much new information about the sustainable refurbishment concepts of exterior walls is needed. On the other hand, the building authorities considering their role in the process want to avoid a situation where their give guidelines or recommendations about the use of specific solutions. Thus the availability of recognized standards and design guidelines is emphasized.
- reinforcement of informative support and dissemination of information about sustainable refurbishment concepts on national levels
The structure of the building sector is fragmented and there is an extremely large number of actors and large inhomogeneity of actors involved in building processes. Therefore, the information that has been developed on European level about the sustainable refurbishment concepts of exterior walls does not easily reach all actors that would need this information. There is a need to develop the availability of information about refurbishment concepts which are relevant in national context considering the climatic conditions and the quality of the existing building stock. This information should be made available so that designers and other actors would easily access it for example through easy-to-use data bases. However, the reliability of information should be ensured and on the other hand the trust on the good quality of information should be ensured by placing the information on web-pages of recognized local actors that deliver and disseminate guidance for building and construction.
- development of effective incentives for sustainable refurbishment of exterior walls
The implementation of the recast Energy performance directive will ensure the consideration of energy performance when buildings undergo major renovation. The energy performance of the building or the renovated part must be upgraded in order to meet minimum energy performance requirements so far as this is technically, functionally and economically feasible. In order to accelerate needed renovations and to avoid situations where needed renovations are much delayed because of financial reasons, effective incentives are needed. The necessary renovations are often delayed and the selected refurbishment methods are sometimes chosen on the basis of financial reasons that may be short-term and imprudent but on the other hand - important from the view point of the financial capacity of some building owners or tenants. Therefore, rightly directed incentives may considerably promote and speed up renovations that significantly upgrade the energy performance and sustainability of exterior walls.
- promotion of training for improved expertise in design and construction of sustainable refurbishment concepts
Different kinds of measures are needed in order to ensure the dissemination of information to a large group of actors that will need improved knowledge about sustainable refurbishment of exterior walls and sustainable renovation of buildings. The specific consideration of the topic should be ensured both in university and polytechnic schools as well as in training courses provided by associations of designers and by building industry.
- continuous support for demonstration
Different kinds of measures are needed in order to ensure the dissemination of information to a large group of actors that will need improved knowledge about sustainable refurbishment of exterior walls and sustainable renovation of buildings. The specific consideration of the topic should be ensured both in university and polytechnic schools as well as in training courses provided by associations of designers and by building industry.
- citizen engagement
Tenants and building owners living in buildings are the end-users of new technologies for building refurbishment. The increase of public awareness of the importance of sustainable building through information campaigns is also needed. One of the biggest barriers for the quick promotion of sustainable building is the low level of knowledge and awareness in the areas of energy by the end user. Launching information campaigns on new energy saving technologies and renewable technologies (which at the same time fulfill the overall requirements of sustainable building as explained in Section 3.2) might help to overcome the distrust by public on the sustainable refurbishment technologies especially when this happened simultaneously with the provision of effective incentives.
Potential Impact:
SUSREF has developed:
-information about the potential impact of the refurbishment of exterior walls,
-concepts for the refurbishment of exterior walls,
-a systematic approach for the assessment and comparison of concepts
-guidelines for refurbishment processes and for building industry
-recommendations for standardisation bodies and policy makers.
The potential impact of the project will be based on the use and exploitation of these outcomes.
Assessed potential impact of the refurbishment of exterior walls on the European level.
SUSREF aimed at making a realistic assessment about the potential impact of the refurbishment of exterior walls. SUSREF assessed on the bases of calculation that that the total CO2equ saving for the single family houses in Europe is 55.4 Mt and for the multi-story buildings 16.8 Mt per year. Thus in total the assessed saving is 72 Mt during 20112020 per year. This was calculated on the basis of U-value changes and heat degree days by using the proposed refurbishment concepts by the SUSREF partners from different parts of Europe and by using realistic assumptions about the rates of refurbishment.
Business strategies of the SME partners
SMEs have worked out their business strategies. The SMEs created business plans in order to meet the SUSREF goals of dissemination of the R&D results and to take up the results in the businesses of the partners and wider industry delivering either services or producing materials, components or other tangible solutions for sustainable façade refurbishments in various parts of Europe. With a business plan the entrepreneurs analysed the strengths and weaknesses of their own capabilities. The business plan works for a business to look ahead, allocate resources, focus on key points and prepare for challenges and opportunities.
SUSREF has developed knowledge, methods and concepts that can be utilized as expert services offered in the façade structure condition surveys:
-Energy and circumstance simulations
-Life cycle assessment
-Building physics assessment
-Facade renovation services
-Facade renovation designs
Sustainability is one of the main targets in development. Customer, owner and inhabitant want to have a healthy living environment. Because of increasing energy costs our clients need energy efficient buildings. The client needs solutions which take into consideration the technical functionality and economy. The need for the services will be for the whole lifecycle of the building e.g. for the following reasons:
-changes of the owners of the buildings
-changes of the users of the buildings
-changes in legislation
The clients of the project partner Vahanen are house owners, inhabitant associations, property owners, construction companies, developers etc. The clientele varies from country to country. The target market for specialist services will be at the beginning the countries they already are active: i.e. Finland, Estonia, Russia, Romania, UAE and India. EKK assesses that potential exists on the big area of Russia and Ukraine. The other SMEs have domestic or EU market areas.
Vahanen, Repair and EKK also made quantitative assessments about the increase in turnover and workplaces as follows:
The implementation of the systematic approach
The implementation of the systematic approach for the development of new concepts and for the development of expert services will require wide expertise in SMEs. Thus the implementation of the proposed process fits best for enterprises that not very small.
On the basis of the experiences, the systematic approach was found feasible and useful because it supported the product concept developers to:
-iterate and optimize material and structural choices
-compare alternative solutions
-investigate the feasibility of new and innovative solutions
-avoid risks
-assess long-term impacts both from the view point of building performance and environmental and financials impacts
-consider both functionality and process related aspects
-develop systems with help of which clients are supported to set targets for refurbishment works.
Dissemination of results
The main methods and activities with the help of which the outcomes of the project are disseminated are as follows:
-Business strategies and business activities of the SME partners of the project
-With help of the developed business strategies and new business activities, the SMEs of the project will
-adopt new concepts, new processes and new services, and
-disseminate the information about new services and concepts when networking and doing business.
New research foreground of the research institutes and universities
The outcomes of the project will be made use of in on-going and coming research projects and contract projects. For example VTT will utilize and disseminate SUSREF results in the current group of projects Ownership in sustainable building (OKRA) which develops new processes for municipalities and owners when they want to support both professional as well as small builders in sustainable renovation and refurbishment. The aim is to develop for cities processes for consultative steering which encourages builders to adopt sustainable and energy efficient concepts for building renovation.
SUSREF Workshops
The outcomes of the project have been introduced and discussed in workshops in the UK, Spain, Norway and Finland. In all of these workshops a remarkable number of important stakeholders participated, listened to the results and participated to the discussion about how to further disseminate results.
Recommendations
SUSREF has developed guidelines and recommendations for building industry, standardisation bodies and policy makers. The project has not succeeded well in disseminating these recommendations but it is still searching for possibilities and support in dissemination. The recommendations for standardisation bodies have been given to the representative of the Confederation of Finnish Construction Industries and its president for building regulations and standardisation to be further promoted in international networks and organizations.
Teaching and education
The results from the SUSREF project are being presented to students in Cardiff University engaged in postgraduate studies at Masters and PhD level in the general areas of building and sustainability. Cardiff University is currently developing plans for a Masters in Building Conservation which will incorporate findings from SUSREF research as a major component.
Training courses
The research organizations VTT, TECNALIA, BRE and SINTEF and their staff often participate as lecturers in different kinds of training courses. The researchers will utilize the project material and disseminate results in coming events which train professionals in sustainable renovation and refurbishment. Because of the importance of the matter, these events will be many during the coming years.
Scientific articles
The project researchers have written manuscripts for scientific articles and conference papers. This is the best route to disseminate the results for the research community. Existing article and papers for refereed journals and conferences are as follows:
Tarja Hakkinen, Systematic method for the sustainability analysis of refurbishment concepts of exterior walls, Manuscript submitted to Construction and Building Materials, Reviewed and preliminary accepted with a request for few changes, Changes made and manuscript resubmitted.
Abstract: Because of the age of the European building stock and because of the new energy performance regulations, safe and efficient concepts have to be developed for the refurbishment of exterior walls. The objective of this paper is to explain the method that was developed in the European SUSREF project for the analysis of refurbishment concepts, and describe how the method was effectively implemented during the project. Both generic refurbishment concepts and company specific solutions were developed for the refurbishment of building external walls. All concepts were systematically assessed with help of the method. The method includes a list of performance criteria and detailed guidelines for the assessment. Important aspects include not only the aspects of technical and functional performance but also process related aspects and life cycle aspects. The process related aspects should not be limited to technical feasibility but also consider the impacts caused to neighboring buildings and their users. Life cycle aspects should cover both environmental as well as financial aspects. The approach was tested during the project and it was found suitable both for the development of new innovative solutions as well as for the improvement of more conventional solutions. The approach is also recommended to be made use of in the development of design codes for refurbishment concepts of exterior walls. A systematic method should also be used in the dissemination of information about recommended refurbishment concepts for designers.
Tomi Toratti et al. Durability considerations of refurbished external walls. A manuscript to be be submitted to Construction and Building Materials.
Abstract: This paper draws attention to some of the main findings and results of the European project: Sustainable Refurbishment of Building Facades and External Walls. The material presented includes only some analyses cases which were carried out during the project. This topic has a have high industrial relevance and the results may be, to a large extent, utilised as recommendations for refurbishment projects.
In planning of a refurbishment, there is no point to try to prolong the service life of the original concrete core if the limit state of the service life has already been reached at the time of refurbishment. The extending of service life is only reasonable by a coating if the carbonation has not reached the depth of reinforcement.
Erkki Vesikari R.M. Ferreira. Simulation technique for service life assessment of façade refurbishment. A paper submitted to IALCCE conference. Third International Symposiun on Life-Cycle Civil Engineering. October 3 - 6.2012. Vienna Austria
ABSTRACT: The EU Research Project SUSREF proposes as its outcome sustainable concepts and technologies for the refurbishment of building facades and external walls. One of the tasks in the SUSREF project was to predict the performance and service life of the proposed refurbishment concepts.
Erkki Vesikari and R.M.Ferreira. Service Life Assessment for refurbishment concepts of concrete façades. fib Symposium: Concrete Structures for Sustainable Community STOCKHOLM 2012 11-14 June 2012 Royal Institute of Technology (KTH) Stockholm, Sweden
Abstract: The EU Research Project SUSREF proposes new sustainable concepts and technologies for the refurbishment of building facades and external walls. As one part of the project it was necessary to identify the volumes of needs of refurbishment in the EU and in neighboring areas and to evaluate the meaning of this in terms of environmental and economic impact and business potential. Within the tasks of the SUSREF project was also the service life assessment of the proposed refurbishment concepts of building facades and external walls. A simulation software, developed at the Technical Research Centre of Finland, was used to assess the performance and possible durability risks of the refurbishment concepts. The simulation software is able to emulate the temperature and moisture variations in a cross-section of the wall and to apply temperature and moisture sensitive degradation models at critical points of the structure. The software was applied for analyses of the refurbishment concepts in several European climates and with various material options. In this paper some results of the analyses are presented.
SUSREF Publications
The main results of the project are also reported in three publications which are available on the VTT web site:
http://www.vtt.fi/publications/?lang=en
The VTT publications register is available also via WWS, the worldwide portal of science and research publications.
The final reports of the project are as follows:
-Sustainable refurbishment of exterior walls and building facades. Final report Part A. VTT Technology 30. Espoo 2012
-Sustainable refurbishment of exterior walls and building facades. Final report Part B. VTT Technology 33. Espoo 2012
-Sustainable refurbishment of exterior walls and building facades. Final report Part C. VTT Technology 36. Espoo 2012
SUSREF web page
The project has a web page where all SUSREF deliverable are available. VTT will maintain the page and offer all project research outcomes for use for related coming research projects.
http://cic.vtt.fi/susref/
List of Websites:
http://cic.vtt.fi/susref/
Coordinator Dr Tarja HAkkinen e-mail: tarja.hakkinen (at) vtt.fi