Planning Responsible Retrofit - Sustainable Development Foundation
Contents
1. 8 Planning responsible retrofit of traditional buildings Occupation use Just as the forms of traditional buildings vary widely so do their occupation and use Understanding the history of use and how this has changed is also important as it gives clues to what might work and what might go wrong For example moisture levels will differ considerably with different building uses and lifestyles A consideration therefore is to make sure that planned retrofit measures are appropriate for both current and future occupiers of a building Different building users also have different energy use In most buildings the greatest energy use is for heating the building However office based workers often use far more energy on appliances than heating An elder2. How to achive a responsible retrofit 19 Jack Kelly 6 9 9 O 0 9 9 0 6 9 6 Look and learn 9 6 9 9 06 0 9 0 6 0 9 0 0 9 0 GO 9 9 O9 0 9 0 9 0 GO 0 9 0 9 9 GO o 0 6 0 0 9 0 o 9 0 9 0 G9 0 9 9 9 Once retrofit works have been completed it is important to observe the effects on the building both intended and unintended to monitor results and to learn from successes and failures In order to understand how things change it is helpful to check and record how things are working before you undertake the retrofit measures This can also be part of any assessment process Energy savings check energy bills before and after retrofit Savings can only be assessed where there is adequate record of energy use prior to retrofit This is a common mistake in retrofit projects More than one year s
3. 4 Understanding risks Understanding your building and the challenges ot its retrofit is largely about understanding risks These risks can be broken down into three overarching categories 1 Risks to building fabric and human health 2 Risks to heritage damage to and loss of historic fabric impact on neighbourhood or community 3 Risks to achieving expected energy savings resulting environmental impact This chapter identifies these broader risks and explains exactly why it is necessary to consider them It then gives examples of specific risks likely to be encountered with each retrofit measure taken from real projects with action points for guidance on page 16 and 17 1 Building health risks to building fabric and human health Inappropriate retrofit measures can lead to unintended consequences such as condensation and mould growth or more serious fabric decay such as wet and dry rot These issues arise when moisture from poor building condition internal moisture generation or from rain is prevented from drying out or channelled into cold areas through poor design or installation of measures Trapped moistu
4. Planning responsible retrofit of traditional buildings Contents era 4 2 Gening it Nghi a 6 3 The challenges of responsible retrofit 8 4 Understanding risks sss 12 5 How to achieve responsible retrofit 18 20 T PEO E 22 ss ee 3 Planning responsible retrofit of traditional buildings Contents 3 1 Introduction Retrofit principles 1 Think about ENERGY ENVIRONMENT HERITAGE COMMUNITY 2 Take a Whole Building Approach Who is this guidance for This guide 15 for anyone involved in a project aiming to reduce the energy use of a traditional building through technical interventions This is what 15 primarily meant by retrofit The guidance will be useful for e Building owners managers and occupiers e Architects assessors and designers e Project managers Building contractors Why retrofit your building There are many reasons for retrofitting your building These include the desire to reduce carbon emissions to save money to improve comfort and health to reduce worry about fuel
5. 6 Planning responsible retrofit of traditional buildings i o Healthy buildings Retrofit is an opportunity not only to improve energy use but also to improve comfort and health for a building s occupants Discomfort and ill health in buildings are often connected with moisture problems due to poor maintenance Inappropriate repairs and alterations or inadequate heating All these omissions also affect the health of the building fabric Toxins such as radon overheating and usability it is important for occupants to be able to control their environment are essential considerations for health and comfort A health focused strategy can prevent long term side effects illnesses and costs and short term failures Balance Achieving responsible retrofit often requires compromises between different values It also requires a Whole Building Approach whereby there Is integration of the fabric measures such as insulation new windows draught proofing and services particularly ventilation heating controls and renewables along with proper consideration of how people live and use the building All of t
6. 10 Planning responsible retrofit of traditional buildings Interactions Technical Interactions There are complex inter relationships between the different thermal elements of a building walls floors roof windows doors the space heating and ventilation systems the use of the building and its context If alterations are made to one element then there may be knock on effects with other elements For example when Introducing better performing windows e space heating demand is reduced so the heating system will need adjustment air leakage will be reduced so additional ventilation may be required adjacent walls will become cooler in relation to the windows so without good ventilation the risk of condensation on the reveals is increased For this reason it is essential to take a Whole Building Approach in a Joined up Process Conflicting aims While energy efficiency 15 often the primary aim of most retrofit strategies there may be different reasons for this such as the desire for cost savings reductions in CO emissions or improved comfort Those involved in the retrofit at different stages may have varied and conflicting aims or priorities for example occupant health issues or historic character of the property The Joined up Process can resolve these conflict
7. O 5 How to achieve responsible retrotit The Responsible Retrofit approach is based upon a Whole Building Approach in a Joined Up Process In this way the main benefits to Energy and the Environment Heritage and Community and Building Health of people and fabric can be achieved The Whole Building Approach means integration and balance of e Fabric Measures such as insulation draught proofing glazing rainwater protection ie improvement to pointing and gutters e Services such as ventilation heating thermostatic controls renewable energy and People in regard to how occupants understand use and maintain their buildings These all interact with each other It is important to understand that if you insulate a wall then this will to some extent also affect the windows the floor and roof as well as the internal LE be CONTE Eve WEIS The Joined up Process 15 explained on the next page Before this however there are some basic questions which you should ask yourself when contemplating a retrofit project Questions to ask yourself 1 Do you have sufficient understanding If not can you find an expert surveyor designer or installer who does You can learn more by reading the resources or going on appropriate training courses see page 22
8. 6 e 9 9 9 9 0 9 9 Getting it right 7 Historic Scotland Historic Scotland 6 6 0 9 0 9 9 0 0 0 9 9 9 9 0 9 9 0 0 9 9 3 The challenges of responsible retrotit The success of a retrofit depends firstly on understanding the building and its context in sufficient detail and depth Secondly we need to understand that some of the formal standards and methods used by government and industry are incorrect or incomplete Finally it is important to understand the interactions between all these different elements and how different aims for retrofit may conflict
9. This publication has been supported by C t D Historic England Responsible Retrofit Series Construction Industry Training Board ur S BA HIS LHI SL LAN LD Mos M SUSTAINABLE TRADITIONAL Cymin ee le BUILDINGS ALLIANCE lal ALBA ADSMHOR
10. Understanding your building What is your building made of How do the fabric and services work together Traditional buildings differ widely in terms of their style and form as well as in materials see the Resources on page 22 The types of material ie brick stone timber lime mortar cob vary widely in how they deal with moisture heat and structural pressures The type of construction the thickness of walls the sizes and types of window the types of fire place and chimney all affect the energy use the health of the building and influence what can be done For example a thick limestone wall can be warmer than a thin brick construction as well as dealing with rain and moisture better so will require a different approach in retrofit A building with large bay windows will be much more challenging to insulate than one with simple casement windows Some buildings like traditional timber frame can be very draughty but conversely some can be very airtight However technically most traditional buildings work from the basic principles of balance and integration of moisture heat and ventilation within the building type and context On the other hand very few traditional buildings are unaltered or in perfect condition which can create challenges Alterations Buildings which at first may appear similar have often been adapted and upgraded over a long period with for example double glazing loft and other insulation loft an
11. 2 Do you have sufficient capacity in terms of time budget and patience to cope with the disruption If you don t then either delay or plan the work in stages Whatever you do make sure you keep to a Whole Building Approach and Joined up Process 18 Planning responsible retrofit of traditional buildings alr quality All measures but particularly fabric measures affect the rest of the building and the people who live or work in the building Junctions and connections are particularly affected but so are whole systems such as ventilation and heating This is why we need a Whole Building Approach This approach also depends strongly on the Context of the building which means its location exposure to sun rain and wind the historic and community value its condition use and form and the regulations and funding All of these determine the way in which a Whole Building Approach should be carried out and the options and constraints for retrofit WHOLE WILDING APPROACH 3 Is this the right time to do the work What other work is required or will be undertaken in the future Make sure you co ordinate the work programmes on the house to ensure Whole Building integration and best value for money 4 Do you really need to do the work How else can you improve your environmental impact health and comfort or make cost savings Sometimes It Is easier safer and more environmentally friendly to make lifestyle changes and simply to
12. Responsible Retrofit Series STBA SUSTAINABLE TRADITIONAL BUILDINGS ALLIANCE Sustainable Traditional Buildings Alliance STBA The STBA is an alliance of not for profit organisations representing the sustainability heritage and professional sectors in the UK The STBA aims to promote and deliver a more sustainable traditional built environment through high quality research education training and policy The Responsible Retrofit Series of booklets provides short and usable guidance about traditional building retrofit based upon best current research and practice and which is holistic and realistic in its understanding and aims These booklets will help to reduce risk and liability while also improving outcomes in reality not only in terms of energy but also health and heritage They are not tick box guidance because there is unavoidable complexity and uncertainty in the way that old buildings new technologies nature and people perform and interact Furthermore retrofit often involves conflicting values and aims There is no one size fits all solution Responsible Retrofit means taking an informed integrated and ethical attitude to these challenges These guides are here to help people to do this Future planned Responsible Retrofit guides will cover How to Do subjects such as External Wall Insulation Internal Wall Insulation Roof and Floor Insulation Renewable Energy systems and Usable Controls and Services We
13. Historic England 2 Getting it right Responsible retrofit should deliver sustained net reductions in energy use at minimal environmental impact while maintaining or improving the traditional built environment and making a positive contribution to human health Energy savings Environmental improvement Real reductions in energy use reduce costs as well as CO emissions and ultimately contribute to improving everyone s fuel security Long term savings are best achieved through simple and robust technical measures which are easy to use and maintain Reducing CO emissions is also essential in helping to reduce global warming Responsible retrofit also minimises the embodied impact of materials and construction in the build process and the mitigates the impact on resources and habitats Heritage protection and enhancement Most traditional buildings including those that are listed can be upgraded with at least some retrofit measures to fabric or services With appropriate care and user engagement It 15 possible to achieve sustained reductions in energy use without damage to buildings or to streetscapes Where buildings have fallen into disrepair they can be enhanced by sympathetic renovation and proper maintenance which not only prolongs their life but also contributes to reductions in energy use Unbalanced draughty loads of heat loss traditional features maintained
14. SPACE HEATING Marianne Suhr Orientation and geography can affect the risks and benefits of some retrofit measures Robyn Pender Historic England The historic context will have an impact on what should be done to a building eee The challenges of responsible retrofit 9 Responsible Problems with standards and regulations Retrofit ot Traditional Traditional construction standards data and modelling Buildings As identified in the Responsible Retrofit of Traditional Buildings Report see Resources section page 22 there are still significant errors in the way that traditional buildings are treated in building standards regulations and assessment systems typically computer models This means that much of the standard guidance and many of the current government funding schemes as well as commercial product certifications are misleading or incorrect This is partly due to the gap between best current research knowledge and the adoption of such work by standards and regulatory agencies and partly due to the uncertainty of data and science of traditional buildings something which will take many years to resolve In particular the following should be noted 1 We have a limited picture of how traditional buildings perform thermally ie in terms of keeping occupants warm There 15 good evidence to suggest that overall they perform much better than the assumptions made in standard assessments This is important as the asses
15. can damage or obscure decorative 12 Planning responsible retrofit of traditional buildings An extreme outbreak of dry rot and mould due to moisture ingress and lack of drying An insensitive external wall insulation application which damages the beauty and character of the whole street Brian Ridout Historic England Anna Marie Pagano 9 9 0 0 9 0 9 9 0 9 0 9 9 0 O 9 6 0 0 9 9 9 9 0 9 0 9 9 9 9 9 9 6 ceilings or internally visible roof structures Historic floors may be damaged when insulation 15 retrofitted Ventilation systems heating
16. data either side of retrofit is needed to take account of variations in energy use from one year to the next Any changes in occupation use or weather conditions need to be taken into account Technical risks check annually Technical risks can be simple to monitor Renewable energy systems can be checked by meter readings and fuel bills although underperformance due to a technical fault may require an expert review For fabric measures if loft insulation has been increased annual checks for any signs of mould forming on rafters would be advisable Inside the property surface mould and condensation on any cold spots are easy to see The most challenging areas are in wall floor and rafter insulation where failures can build up over years It is therefore advisable to leave access in the most vulnerable areas for example by a floorboard which can be easily lifted to check for mould and damp You can often smell and feel damp problems even If you haven t got a damp probe meter If in doubt consult an expert who understands old buildings Checking under the floorboards by the wall is often a good way of monitoring the risks of insulation 20 Planning responsible retrofit of tradit
17. habitats TE ERE 50 Direct rebound effect Comfort taking by increasing internal temperatures e Under heating of building prior to retrofit Inadequate heating controls post retrofit e Lack of user understanding of building controls D a pH ONE C TUM EET e Narrow focus of savings assessments Lack of understanding of environmental impact 14 Planning responsible retrofit of traditional buildings 9 9 0 0 0 9 9 0 GO 9 0 9 9 O 9 9 6 0 0 9 O 9 0 9 GO 9 0 9 9 9 9 06 6 KEY TO IMPACTS ENERGY ENVIRONMENT 7 HEALTH BUILDING AND HUMAN HERITAGE COMMUNITY GOOD BALANCE e Fabric Services People BUT A bit draughty and high energy use Possible maintenance problems SINGLE MEASURE UNBALANCE e Fabric not coherent Services ventilation stressed e Moisture mould health issues Still lots of energy use Building health problems Heritage affected FABRIC FULLY INSULATED BUT UNBALANCED SERVICES e Sufficient ventilation Services stres
18. streetscape Moisture safe design and detailing Suspended floor Heritage impact internal e Check historic value of floor insulation Moisture risk Moisture safe design and detailing High Ventilate below floor Check effect on building ventilation Solid floor Heritage impact internal e Check historic value of floor insulation e Moisture risk e Moisture safe design and detailing High Particular issues at floor wall junction Window e Heritage impact internal and e f uncertain take expert advice external appearance for heritage moisture and thermal High e Moisture risk change in ventilation strategy for windows thermal bridging e Whole Building Approach is essential Airtightness e Heat loss reduction e Understand existing and post e Moisture risk both to fabric and retrofit ventilation effects and put in High human health additional ventilation if required Ventilation Heritage impact from ventilation Understand existing ventilation grills ducting New systems must be designed and High Image Robyn Pender Historic England Risks from services MEASURE MAIN RISKS ACTION LEVEL OF RISK amp CARE REQUIRED Mechanical Heritage impact from inappropriate Understand existing heating cooling Low systems installations pipework flues etc and ventilation demand New systems Heat loss from incorrect type or use must be designed and installed sensitively e Systems must be easy to operate and effective Users
19. systems and renewable energy systems can also compromise the heritage value of a building particularly if installed insensitively Of course retrofit can also be a chance to correct previous mistakes particularly where they are causing ongoing damage to fabric or health for example inappropriate renders blocking up of ventilation etc 3 Risks to achieving expected energy savings resulting environmental impact As building elements are connected to one another measures to improve the performance of any one part need to consider adjacent parts and their effect on the whole building For example the effectiveness of internal wall insulation can be reduced by an increase in heat loss through window reveals if they are not also Comfort taking is a common and insulated This is one reason why a Whole Building Approach is important understandable consequence of improving insulation and reducing draughts Even after buildings are retrofitted correctly some of the gains In energy efficiency may not result in actual reductions in energy use This happens for example when occupiers run the building at higher internal temperatures because it is now possible to do this without prohibitive cost This direct rebound effect aka the comfort factor can be beneficial to occupant wellbeing but it means that savings will not be as high as may have been predicted Alternatively the financial savings which are gained by reducing energy use ar
20. welcome feedback from retrofit projects We encourage people to share their knowledge and experience with us as part of a collaborative national endeavour to improve and sustain our traditional built environment Visit our website www stbauk org This publication has been supported by the following organisations pm AAA Historic England istoric Englan Construction Industry Training Board The CITB works with employers to encourage training helping to build a safe professional and fully qualified workforce It also develops specialist training for conservation and retrofit work HISTORIC SCOTLAND h ADS AA HO R Historic Scotland is an Agency within the Scottish Government and is directly responsible to Scottish Ministers for safeguarding the nation s historic environment and promoting its understanding and enjoyment Authors Neil May and Nigel Griffiths Cover image by Nigel Griffiths Graphics by Isabel Carmona Design by Jenny Searle Associates STBA 2015 9 9 9 We are the public body that looks after England s historic environment We champion historic places helping people to understand value and care for them Lywodraeth Cymru Welsh Greemment Cadw is the Welsh Government s historic environment service
21. Controllable passive stack using existing hearths and stairwell rooflight or whole house MEV ventilation with Humidity sensitive Demand Control Decision depends on level of airtightness layout disruption etc SOME GOOD OPTIONS PEOPLE 4 Consultant surveyor designer contractor works with owners to increase understanding of occupant role in building health energy use and importance of maintenance The whole retrofit project is undertaken responsibly using a Joined up Process see page 19 BEFORE Above average energy bills Above average CO emissions Talking es ae AFTER 60 or more reduction in energy gas and electric bills and CO emissions which are now considerably lower than UK average Ongoing monitoring Peeling wallpaper and mould in some areas High RH in bathrooms leading to mould High VOCs in kitchen Insect attack in roof timbers Children asthmatic Low levels of comfort and health Rooms are now drier no mould on window reveals RH and VOCs now safe for health fabric Timber decay arrested by drier conditions Health improvements for all the family Heritage community Conservation area Original sash windows Original cornices in front rooms Visual impact on back minimal Front kept same Sashes preserved Part of cornice covered removed or re moulded if costs allowed Building has new lease of life Nigel Griffiths STBA Roger Curtis Roger Curtis Aereco
22. EQUIRE Heat loss from incorrect type or use 16 Planning responsible retrofit of traditional buildings installed sensitively Systems must be easy to operate and effective Users must be informed properly External wall Heritage impact both to building e Assess building properly for condition High insulation and streetscape context and interactions If uncertain e Moisture risks leading to rot of fabric take expert advice for heritage Poor Indoor Air Quality IAQ from moisture and thermal strategy poor ventilation and damp Take whole building approach Heat loss from wet walls or thermal especially junctions and ventilation bridging Use trained qualified contractors Internal wall Heritage impact internal e Assess building properly for condition Very high insulation Moisture risks leading to rot of fabric context use and interactions If Poor IAQ from poor ventilation and uncertain take expert advice for damp heritage moisture and thermal Heat loss from wet walls or thermal strategy bridging Take whole building approach especially junctions and ventilation Use trained qualified contractors Roof loft Moisture risk e Ensure ventilation at eaves and check insulation roof space occasionally Low Roof rafter e Heritage impact internal or external Ensure historic ceilings or roofs are insulation Moisture risk not damaged Ensure over rafter Medium insulation takes account of heritage values of roof and
23. Heat island effect in cities affecting internal spaces 5 DT Risks to heritage community i RISK CAUSE Significant change in External wall insulation covering up significant masonry historic render or external appearance architectural details including decorative brickwork etc loss of historic fabric Inappropriate window or glazing replacement e Incongruity of alterations with overall streetscape e Insensitive renewable technologies on historic roofs or in sensitive streetscapes Change in internal Loss of original features such as timber mouldings and plasterwork appearance and or Loss of original window frames and glazing 5 loss of historic fabric Insulation over historic floors e Ventilation and plumbing electric intrusions Risks to achieving expected energy savings environmental impact d RISK CAUSE 85 Energy improvement naccurate assessment and modelling 29 not as large as expected poor product quality Poor design installation use Failure to take Whole Building Approach po Environmental impact High embodied energy of retrofit measures increased Failure to achieve energy reductions p 2 Use of rare resources or materials from vulnerable
24. There is a range of help guidance and training available to help owners and contractors achieve responsible retrofit As made clear through this document the understanding of traditional building retrofit is still in development and there are many uncertainties All guidance is therefore prone to becoming out of date and Retrofit af misleading All guidance including that listed below should be taken as guidance RE Traditional not gospel truth and should be used in conjunction with other guidance and with ner Buildings this document where possible Guidance on individual measures or issues should not be taken in isolation Strategies to retrofit buildings should consider how the whole building functions both before and after retrofit Finally new guidance training and research 15 currently being developed so it 15 recommended that those involved in retrofit subscribe to updates and new resources from named organisations regularly Responsible STBA Responsible Retrofit Report The Responsible Retrofit of Traditional Buildings Report 2012 was commissioned by The Department of Energy and Climate Change DECC This comprehensive report identified policy issues and errors in the existing conventions for assessing thermal performance and carrying out moisture risk assessment in traditional buildings The report also identified research needs and addressed delivery issues such as a lack of training at all levels of the retrofit process The report is a
25. bills and supply and to improve the value of a property Some people are also obliged to retrofit because of legislation or building regulations What is this guidance for It is to enable people to reduce energy use in buildings in an effective way which is also good for health heritage and the natural environment This is what we mean by responsible retrofit Why is this guidance necessary There is increasing evidence that the retrofit of traditional buildings and indeed all buildings over the past few years has not led to the expected reductions in energy use and has harmed the building fabric heritage or health of building occupants This Is for three primary reasons e Incorrect standards and assessment of traditional buildings Single or narrow focus approach to both risks and retrofit measures Disjointed and poor quality building process This guide makes clear where existing standards and information are wrong It shows the need to consider three broad areas of risk Energy and Environment Building Health health of both fabric and people and Heritage and Community Sometimes compromises must be made between these values to get the best overall outcome and this guide demonstrates a practical approach to this problem It identifies and promotes a Whole Building Approach which integrates Fabric Services such as heating and ventilation and Human Behaviour with the Context of the building We show how this balanced ap
26. ck Single glazed sash windows Old shutters previously removed Partially insulated roof space Uninsulated timber floors to front rooms BEFORE 1980 s era gas central heating No ventilation windows and flues blocked shut Ground or air source heat pumps possible Photovoltaic panels solar water heating and woodburning stoves all require planning consent No renewables or low carbon technologies BEFORE Young family Children have asthma No understanding of building health or energy WHAT MATTERS Energy environment Subject to driven rain at front but protected by street condition some dampness in walls and attics cornice Original timber floors SOME GOOD OPTIONS FABRIC Vapour open EWI to back and gable Moisture open IWI to walls or blown IWI behind existing linings Or insulated lime plaster internally Repointing to front elevation repairs to gutters lowered ground levels Shutters reinstated and working and or secondary glazing or double glazed units in existing sashes and or thermal roller blinds Moisture open insulation to rafters maintaining air flow above Airtightness improved Insulation between ceiling joists Roof ventilation Timber floors lifted draught proofed and insulated ventilation checked and enhanced SOME GOOD OPTIONS SERVICES New condensing boiler TRV s in all rooms set back heating controls Radiant heating panels in bathroom and kitchen
27. d cellar conversions extensions subdivisions and changes of use The addition of modern impermeable cement renders removal and closing off chimneys and flues the introduction of more air tight membranes and vapour control layers and the addition of concrete floors are common All these affect moisture movement heat and ventilation both designed and unplanned air movement and may mean different strategies are required in different parts of the building Today nearly all buildings in this country have central heating baths showers and washing machines The extra pressure these modern comforts exert on traditional buildings can be considerable Take a careful look at your building and its construction history It may be quite complex with a mix of old and new work Condition and alterations requiring a multi faceted Condition is also highly variable Dampness and draughts from poor maintenance can approach be the cause of much higher energy use longer term structural problems and risks to health It should be noted that in some cases due to alterations modernisation and poor maintenance the building fabric may be at the limits of its capacity to handle water vapour or rain ingress which can lead to failure if retrofit measures such as insulation or draught proofing are not undertaken as part of a whole building approach or are incorrectly applied
28. e often spent in other ways which themselves use energy This type of indirect rebound effect may mean that the overall impact of retrofit on carbon emissions Is very low or even negative Finally the embodied impact of the retrofit measure and work including the energy use and carbon emissions from in contracting will reduce and may even outweigh the Savings in use Furthermore the use of scarce resources or materials from threatened habitats can harm the environment When all these factors are taken into account often a more modest approach to retrofit is more beneficial to the environment Energy savngs at home may mean environmental impacts elsewhere Taking a balanced approach There are many challenges for responsible and successful retrofit It is important to note that Section 5 explains in more detail how to in reality buildings and Take a Whole Building Approach e Make sure you engage In a Joined up Process people En be quite robust Aim for Balance overall not for perfection in just one area Compromises can work if N we are clear which issues Balance also means being cautious not over ambitious and having enough 7 capacity in both building and financial terms if things don t go quite as planned are really critical and it It is important to note that in reality buildings and people can be quite robust we keep an eye on things Compromises can work If we are clear which issues are really critical and if we
29. eading both in terms of moisture and heat loss This can lead to very inefficient design and considerable mould problems MOISTURE RISK ASSESSMENT The environmental impact of retrofit work AND GUIDANCE Retrofit is commonly measured in terms of its effect on the energy consumption and CO emissions from buildings in use For responsible retrofit the embodied impact of construction and materials should also be taken into consideration wherever possible This can be substantial and sometimes even outweigh any savings in use Retrofit materials require energy for manufacture and transport to site and in many cases they are made from Increasingly scarce resources such as oil or are taken from vulnerable habitats Unfortunately good information and standards are also lacking IL STBA qe oe MAINTENANCE REPAIRS END OF LIFE PRODUCT CONSTRUCTION p OPERATIONAL WATER amp ENERCY LEFT The embodied impact varies with building type and use This applies to OFFICE SEMI DETATCHED WAREHOUSE traditional and non traditional buildings in HOUSE the same way
30. f thereby cutting heating costs energy use and CO emissions However there are also other important ways of reducing these impacts including improvement in services such as heating systems controls and lighting and by the use of renewable energy Different buildings and different occupants benefit from different approaches Not all buildings can be retrofitted and for some buildings and people there are more appropriate ways of reducing environmental impact than technical interventions Why does the retrofit of traditional buildings need a special approach All work on buildings requires an approach which is specific to their context However there are some general qualities of traditional buildings which are worth defining in comparison with modern post 1919 buildings and which consequently require different understanding skills and material solutions Traditional buildings are constructed from different materials and in different structural forms compared with modern buildings and consequently they perform differently They usually heat up and cool down more slowly Moreover they deal with moisture differently allowing rain groundwater and internal moisture from washing cooking and breathing to move in a controlled way into and through their semi permeable fabric They also rely on sunshine wind heating and adequate internal ventilation through windows chimneys and draughts in order to keep dry In good condition and w
31. g what has worked and what needs adjustment or improvement Retrofit is not a fit and forget activity either in terms of learning or in terms of maintenance There are many types of retrofit many uncertainties in the current science and technology and every building and human being behaves differently so there are always going to be many unknowns Retrofit needs to be seen as part of an Individual and national journey which we should undertake with our eyes wide open with patience and with humility If we retrofit responsibly then we can act with confidence and be part of this journey to a better built environment ACT 06 9 9 9 9 9 9 Look and learn 21 eC 0 o Resources
32. hese must be adapted to the context of the building its exposure status condition form etc When these are integrated well a building 15 in balance LEFT In the diagrams we show that an Unbalanced building can be retrofitted to a more Balanced building in a responsible retrofit using a Whole Building Approach The bar charts give a snapshot of the risks and benefits of each The idealised case study on the opposite page gives the details of such a project and may be considered a responsible and successful retrofit project and approach Underpinning the success of any project is a Joined up Process See page 19 for a detailed breakdown of this process More balanced warmer and healthier with slight loss of traditional character Key to impacts EJ ENERGY ENVIRONMENT HEALTH BUILDING AND HUMAN 2 9 HERITAGE 9 9 9 9 9 Case Study Georgian town house in poor condition Some options for a Whole Building Approach retrofit undertaken by a young family CONTEXT Location orientation Bad pointing leaky gutters high ground levels Chimney stack in poor Conservation area Fine brickwork to front Fine window details Internal Heritage community BEFORE Uninsulated 9 solid bri
33. ifferent building elements Historic England Practical Building Conservation Building Environment 2014 Republic of Ireland Environment Heritage and Local Government Energy Efficiency in Traditional Buildings 2010 Roger Hunt and Marianne Suhr Old House Eco Handbook 2013 Changeworks Energy Heritage A Guide to Improving Energy Efficiency in Traditional and Historic Homes 2008 Research and technical material Historic Scotland publishes Technical Papers considering specific issues including Technical Paper 1 Thermal Performance of Traditional Windows Technical Paper 2 In situ U value Measurements in Traditional Buildings Technical Paper 6 Indoor Air Quality and Energy Efficiency in Traditional Buildings Technical Paper 9 Slim profile double glazing Technical Paper 10 U values and Traditional Buildings Technical Paper 12 Indoor Environmental Quality in Refurbishment http www historic scotland gov uk conservation research htm Historic England and Cadw both have ongoing research programmes Training A range of Heritage Conservation and Retrofit training programmes for supervisors and operatives 15 available from the CITB and other providers which includes Energy Efficiency and Retrofit of Pre 1919 Traditional Buildings National Occupational Standards NOS for the retrofit are currently in place and have recently been updated These standards have been used by Awarding Bodies such as Asset Skills the SQA and P
34. ilding s shared history beauty place in the community and social life all contribute to its heritage and community value which must be considered alongside its condition occupant use and location in any retrofit strategy For some buildings the heritage value is indicated in planning terms such as a Listed Building Conservation Area or an Area of Outstanding Natural Beauty AONB There will be planning constraints on how such buildings can be repaired or altered However in many cases the heritage or community value is not formally designated so a sympathetic understanding and sometimes research is required to identify what is significant This is helpful in all cases The appearance and use of some traditional buildings can also be significantly improved and enhanced by retrofit Sometimes an approach will need to encompass a whole street or community area These factors must all be considered to reduce risks to heritage and community See Chapter 4 Understanding Risks 0 HOUSE WITH OLDER OCCUPANTS HOUSE WITH YOUNG SINGLE OCCUPANT vot water M POWER Energy use varies depending on the occupants lifestyle OFFICE IN OLD BUILDING
35. ional buildings Maintenance Appropriate maintenance Is essential both before and after retrofit projects Faulty rainwater systems are one of the most common causes of building failures and this becomes even more critical where solid wall insulation has been introduced An annual clean of gutters and drains 15 highly recommended Chimneys and gable ends are especially vulnerable to water penetration so render pointing flashings overhangs and caps should all be maintained regularly Appropriate repair of roofs masonry walls and render maintenance of seals around windows and doors and regular painting of external timber will reduce the risk of water entering and becoming trapped in the building fabric Gutter maintenance and repair can be tricky sometimes So make sure you have a maintenance plan Nicholas Heath Learning is essential at all levels in the retrofit process among owners designers contractors and subcontractors Learning also needs to be documented and shared between Current and future occupants of buildings so that the history of use and alteration 15 not lost and so that technical risks can continue to be monitored in the longer term Learning about buildings in the widest and deepest sense protects buildings from risks improves energy use and can bring real benefits for both occupier and contractor Continual improvement is possible by looking at energy savings and technical risks and learnin
36. ith regular maintenance the system stays in balance Changes to fabric performance heating and ventilation if not correctly undertaken can change this balance and lead to problems of overheating moulds and ill health Culturally traditional buildings provide local character and a very tangible connection to the past with aesthetic and community benefits All buildings do this but traditional buildings reach further into the past and have greater links to locality and history something which cannot be easily replaced 6 9 6 06 06 9 0 9 9 0 9 9 0 9 9 I piti n i LEA mm CRE ABOVE Traditional buildings be very different in age construction condition and use BELOW Traditional buildings not only perform differently technically but they represent a different way of living and a connection with the past Diffusion losses Historic Introduction 5 lain McCaig Historic England Nicholas Heath Robyn Pender
37. keep an eye on things which are uncertain which are uncertain The three tables overleaf summarise the broad risks which can arise from poorly planned or poorly executed retrofit Understanding risks 13 istock pablo_rodrigues Risks to building fabric and human health 5 4 RISK CAUSE oe a 5 5 T Fabric decay Trapped moisture from moisture closed materials uim including rot e Liquid water from driving rain or leaks infestation Air leakage from inside house onto cold surfaces e Lack of ventilation D e Lack of building maintenance 8 Surface condensation Thermal bridging due to lack of coherent insulation 2251 and mould growth Reduction in ventilation or failed ventilation systems O Mn ET e High humidity levels from use Poor indoor air quality Reduction in ventilation because of improved draught proofing e Inadequate improperly used or non existent ventilation systems e High humidity levels from use and overcrowding 2 Toxins VOCs Radon etc in under ventilated spaces 5 OON EEE E Overheating or uneven Reduction in thermal mass where masonry or solid floors are insulated from 56 temperatures the inside e Increased thermal resistance from insulation generally e Reduction in ventilation lack of purge ventilation options such as window 5 opening for night cooling 5 e High amounts of south facing glazing
38. ly couple in their home might use hardly any appliances at all but have their heating on continuously The energy use and cost effectiveness of varying retrofit measures will therefore be highly influenced by the type of occupant as well as the use of the building Understanding the context of your building Location and orientation The location and orientation of a building makes a considerable difference to how a building performs and what can be done in retrofit Specifically where there is a lot of driven rain or flooding especially in Wales Northern Ireland Cornwall Cumbria and the West Coast of Scotland walls can be very wet for long periods and this will mean that care has to be taken with any insulation or fabric measures and good maintenance of buildings Is absolutely essential In some cases retrofit may not be appropriate particularly where a building has a complex shape or is in poor condition Conversely a lot of sun can also cause problems with some internal wall insulation systems by pushing water into the building during the summer This is called reverse condensation Buildings in cities have different options from those in rural areas due to what is called the heat island effect which makes cities much warmer and sometimes causes overheating problems There can also be issues with security and air pollution which make changes to windows and ventilation more critical Heritage and community context A bu
39. maintain the existing building well E ace ARTES dal ir UN CHEF e DESIGN 1 Assess the building and context a What is the building made of how does it work or not work and what is its condition Is a special survey required b What is the use of the building now and in future what is the energy use what are the moisture levels and Indoor Air Quality Consider monitoring look at past bills check with Health England website for Radon risk c What is the heritage value overall and in specific parts of the building What is the relation to streetscape landscape and community There are lots of things to think about in retrofit of traditional buildings but remember that these are significant and costly changes which may only occur every few decades or even centuries so it is worth getting it right It s important that everyone involved keeps communicating and all learn from the process This is the best way to reduce risks and improve performance 2 Design and specification a Having better understood the building and its context devise a strategy which integrates all issues and has sufficient capacity and caution where there is uncertainty or conflict b Ensure that design follows a Whole Building Approach c Specify low environmental impact products and process wherever possible d Make an exact specification of product wherever pos
40. must be informed properly Renewables Heritage impact for roof e Consult experts community and Low applications planning for heritage risks e Energy loss from incorrect type or use Ensure correct specification and e Rebound effects installation e Inform users Controls of e Moisture risk All controls of systems and windows Medium heating lighting Energy loss from incorrect type or use should be usable intuitive and and ventilation properly designed and specified systems Risks from human behaviour MEASURE MAIN RISKS ACTION LEVEL OF RISK amp CARE REQUIRED Use repair and e Heritage impact e Ensure user owner understanding Medium maintenance e Moisture risk fabric and human of retrofit systems and building health maintenance e Energy loss from services not working Schedules of repairs important properly and from dampness in fabric Build into financial planning Capacity and Heritage impact Ensure there is sufficient Medium caution Health impact understanding skills time and e Energy impact budget for the project Do not undertake over ambitious or complicated measures Look and learn at all times FAR LEFT a not entirely sensitive services installation LEFT maintenance might seem a chore but it is the most important way to keep traditional buildings healthy and efficient see Understanding risks 17 6 9 9 6 0 9 0 6 9 0 6 0 9 0 6 9 9 0 0
41. nce is provided where there is good evidence of success 2 Modelling of building elements where relevant and possible This is often not possible due to lack of good data or skills 3 Principles based guidance this is the main method of risk assessment and guidance wherever there is uncertainty or complexity The five principles of Quality Process Context Coherence Capacity and Caution are explained in detail 22 Planning responsible retrofit of traditional buildings General Guides Society for the Protection of Ancient Buildings Energy Efficiency in Old Buildings 2014 Historic Scotland Short Guide to Fabric Improvements for Energy Efficiency in Traditional Buildings 2012 Historic England Energy Efficiency and Historic Buildings application of part L of the Building Regulations to historic and traditionally constructed buildings 2012 Historic England Energy Efficiency in Historic Buildings 2012 12 guides covering the upgrade of d
42. proach is essential to long term performance Finally it demonstrates the importance of a Joined up Process linking up assessment design construction and use with proper training quality assurance and feedback In summary this guidance illustrates these principles and demonstrates why they are essential factors in avoiding risks and pitfalls and achieving lasting benefits 4 Planning responsible retrofit of traditional buildings What is a traditional building Traditional buildings are generally of solid wall ie not cavity walls or solid timber frame construction which were built before 1919 Traditional construction differs significantly from modern construction having different materials construction methods and design Traditional buildings make up about 25 of the UK s total building stock It is important to note that many traditional buildings have had alterations additions or other changes to their fabric services and use over the past century Traditional buildings are neither pure nor unchanging What is retrofit Retrofit is the process of improving the energy and environmental performance of buildings through technical interventions albeit that to achieve benefits this process often needs to encompass occupants lifestyle changes and involves an ongoing programme of repairs and maintenance A prime focus of retrofit Is on reducing heat losses through building fabric ie walls doors windows floors and roo
43. re and high levels of relative humidity can also lead to increases in mould spores and dust mites both of which may affect human health Many fabric retrofit measures also reduce natural ventilation leading to poor indoor air quality and further moisture build up A good ventilation strategy is therefore essential in fabric retrofit The UK has one of the highest rates of asthma in the Western world which can be attributed in part to high moisture levels in buildings There are also considerable risks to health from poor ventilation in radon areas 2 Risks to heritage damage to and loss of historic fabric impact on neighbourhood or community Heritage 15 a shared resource shared between current owners of a building and future generations and among communities Future owners of buildings will have to live with the alterations made by previous owners Both fabric and service measures can affect the internal and external appearance and heritage value of a building or sometimes a street or neighbourhood This can be for good or bad So understanding and determining the significance of a building or part of a building is an important task Where either external solid wall insulation or window replacement is being considered there is a risk the building s external appearance may be substantially altered Internal wall insulation can result in features such as historic cornicing and architraves being lost or obscured Retrofit measures to roofs
44. roqual to establish level 2 and 3 knowledge based qualifications for the energy efficiency and retrofit market In Wales Agored Cymru offer a course entitled Sustainability and Energy Efficiency in Pre and Post 1919 Buildings CITB are also developing a clear qualifications pathway in Heritage Skills including retrofit issues for people operating in both craft and supervisory areas The Centre of Refurbishment Excellence CoRE runs in depth courses for retrofit co ordinators General training on the repair and conservation of traditional buildings is available through SPAB and the National Heritage Training Group Contractor selection Risks retrofit can be significantly reduced by employing appropriately qualified builders and craftspeople Builders who have completed Heritage Skills training programmes and who hold a CSCS Heritage Skills card will know how traditional buildings function and be aware of the common pitfalls in retrofit Requiring the CSCS Heritage Skills card also embeds quality assurance into the retrofit process amp 6 9 6 06 9 0 0 9 9 9 0 9 Resources 23 For more information WwWw sibauk org
45. s Conflicting aims can cause problems The different effects of Context Context is made up of all these challenges Context of course also gives us character connection diversity and meaning Each building s context is different A strong heritage context may mean improvements to performance rely on services heating renewables and behaviour including maintenance and repair The occupation context of overcrowding can put a lot of pressure on the health of building and occupants particularly if the services and fabric are in poor condition This can dominate performance more than external contexts am EATON exPoSupe Heritage context a careful approach Bu D V amp Corp Ton LIFESTT UK LOCAL 9 9 9 The challenges of responsible retrofit 11
46. sed e Moisture mould health issues e Less energy use but more ill health Heritage affected FABRIC INSULATED AND VENTILATION INSTALLED BUT PEOPLE CONFUSED More energy use than needed Confusion and some ill health Heritage affected MORE BALANCED FABRIC INSULATED SENSITIVELY SERVICES INSTALLED PEOPLE UNDERSTAND AND HAPPY TO USE e Energy savings plus some renewables warmer and healthier Heritage less affected or improved amp 6 9 6 06 06 9 9 9 9 9 9 0 9 0 9 9 9 9 Understanding risks 15 The Whole Building Approach Risks from specific retrofit measures The key risks arising from specific retrofit measures are summarised below in regard the three aspects of a Whole Building Approach Fabric Services and Human Behaviour The fourth essential A a consideration is the building s Context which significantly affects the level of risk 1 Soy CU Rala Risks to building fabric MEASURE MAIN RISKS ACTION LEVEL OF RISK amp CARE R
47. sible to ensure that lower quality products are not substituted e Include feedback and QA process In the specification and tender documents 3 Installation a Ensure that contractors have sufficient training understanding and interest in the responsible retrofit approach b Ensure that contractors price the Whole House Approach and have feedback and checks agreed with designers and client c Ensure that a clerk of works or suitably trained person is on site with responsibility for the Whole Building Approach d Ensure regular checks of detailed design e If necessary use air pressure testing and thermographic survey for QA check BELOW Feedback and learning are essential 4 Use and maintenance a Leave the occupant with a comprehensive user manual written in Plain English with clear diagrams b Run through services and fabric measures to show the occupant the benefits of correct use and maintenance Prepare a clear maintenance manual this can be one sheet with dates for work estimated costs and contact details for the relevant tradespeople Feedback and learning at every stage Wherever there is an uncertainty particularly around fabric and health risks it is essential to put in some kind of monitoring and feedback mechanism See section 6
48. sment models including the Standard Assessment Procedures SAP and RdSAP which support Energy Performance Certificates EPCs can overestimate the cost savings available through retrofit and make measures like insulation seem more beneficial than they really are 1 Fr Solid Wall Insulation in Scotland 2 Building Regulations apply to any major retrofit in a number of ways including provision of ventilation Part F and thermal requirements However in the thermal requirements Approved Documents Part L1B there are important exemptions hariari anis Md tm and conditions for traditional buildings of permeable fabric which are often not i ete Cache rer understood or missed by assessors and those enforcing regulations 3 There 15 a limited knowledge of how moisture moves in and out of solid wall construction in particular what happens moisture movement when Insulation is added and natural ventilation 15 reduced The standards being used particularly BS5250 are partial in this regard and can be misleading Amendment of moisture standards 15 currently being addressed by the government with STBA assistance Nonetheless this will remain an area of considerable uncertainty and complexity for many years to come 4 The standards advice and certification of internal wall insulation IWI for solid walls are currently wrong or misl
49. vailable at http stbauk org resources stba guidance and research papers Guidance Wheel The STBA Guidance Wheel 15 a free to access online tool which helps to enable informed decision making about retrofit Strategies Having set the context for a specific building users can select measures for Its retrofit and the Wheel then flags up related measures which need to be considered together with the reason for the connection For example wall insulation 15 linked to window refurbishment for reasons of air tightness and indoor air quality The Wheel also provides an assessment of the level of technical risk for any particular measure highlights its potential impact on heritage and identifies any reasons why the savings predicted may not be realised in full The Guidance Wheel is available at http responsible retrofit org wheel Moisture Risk Assessment and Guidance The purpose of this guidance is to provide the basis of an integrated and holistic approach to moisture risk throughout the design construction alteration repair M 0 ISTU RE maintenance and use of buildings The scope of the guidance Is work on all buildings RISK ASSESSMENT both new and existing and all building elements However it is particularly relevant AND GUIDANCE to retrofit This technical guidance is developed from an understanding of the underlying building physics and provides three possible approaches depending upon the context 1 Prescriptive Guida
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