There is a growing concern for evidence of poor energy efficiency performance of solid-wall buildings – collectively those pre-1919 – following interventions that should offer improvements. Worse, energy efficiency upgrades are proven in some instances to cause accelerated degradation of the existing building fabric. Improved design and technical decisions are necessary for positive outcomes for occupiers and the physical impact on traditional buildings.
The Ecobuild seminar on Thursday 6th March, ‘Solutions for improving the energy efficiency of traditional and listed buildings and those in conservation areas’, was very popular with standing room only. The speakers were:
Neil May, Technical Lead and Co-Chair, Sustainable Traditional Buildings Alliance (also seminar Chair)
Colin King, Associate Director, BRE Wales
Roger Curtis, Technical Research Manager, Historic Scotland.
King kicked-off the 90 minutes by outlining ‘unintended consequences’ of well-meaning interventions; problems where none previously existed are estimated to number 74. As a typical example cold-bridging occurs where continuity of external insulation is broken; this can cause condensation and mould growth. When things go wrong such problems can exacerbate the rate of degradation of building fabric, and impair the quality of the internal environment for occupiers.
King offered reasons for these problems and associated solutions:
1) The initial assessment of the existing building is often flawed with inappropriate data collected or system of intervention selected – a whole building approach is necessary;
2) The means of thermal modelling is based on new-build construction and general weather data – this needs to be developed to suit actual construction and a building’s specific location, and additionally needs to measure relative humidity and vapour pressure;
3) Workmanship and knowledge on site needs to improve for better execution and decision-making.
Curtis picked up the thread and shared practical experiences of thermal upgrade projects in Scotland. Key messages included: the need to consider the building holistically, and in particular to value the embodied energy in the existing fabric; to recognise the importance of ventilation as affects indoor air quality – which brings into question the suitability of an ‘air-tight’ solution; and to have a durable and resilient approach to material selections and detailing of work – all three speakers concurred cost has an impact on quality. King stated he would, ‘rather do 80% of the projects correctly than 100% incorrectly’.
May presented the challenge as a conflict of values: heritage versus comfort to occupiers. The challenge is compounded by a broad lack of understanding of the performance of traditional buildings, combined with industry guidance available focused solely on new build – such as building regulations, British Standards, CE marking and so on. There is currently a vacuum of appropriate guidance for energy efficiency upgrade work to traditionally constructed buildings. As King pointedly remarked, ‘…the industry is almost unregulated’.
To aid better decision-making for a whole-building solution Department of Energy and Climate Change (DECC) funding has supported STBA to develop a Guidance Wheel and associated Knowledge Centre. These tools will be launched on March 12th 2014 and be freely available on the STBA website.
An overview of the Guidance Wheel revealed a user-friendly interactive programme which diagrammatically clarifies the impact of one decision upon another element of the building: it is immediately apparent where gaps in decisions exist and prompts the user to consider all aspects. The wheel leads the user to relevant information available to access on the associated Knowledge Centre.
The tools seem intuitive to use and will provide vital assistance to early decisions in developing a scheme for energy efficiency upgrade. Although solutions for appropriate assessment, thermal modelling and on-going monitoring of interventions to traditional buildings require further development, this tool plugs a knowledge gap that the industry is guilty of not having addressed effectively to date.
Experiment with the Guidance Wheel and share your thoughts here on how it works.
Is information on the Knowledge Centre helpful?
When putting it into practice does it help in considering a whole-building approach?
- The STBA document Responsible Retrofit of Traditional Buildings publication (2012) freely available to download from its website.
- Historic Scotland’s schemes are documented as Technical Notes and Case Studies freely available on their website.