A new framework for the retrofitting of dwellings for improved energy efficiency is set out in PAS 2035 from BSI, writes professor John Edwards
Professor John Edwards
Many concerns about construction quality put the blame on poor workmanship. However, with retrofitting of buildings, there are deeper issues. Poor understanding, inappropriate design and the wrong approach have also been at fault. This has led to a major rethink on the way we make buildings more energy efficient through retrofitting.
The recently published BSI (British Standards Institution) PAS 2035: 2019: Retrofitting Dwellings for Improved Energy Efficiency – Specification and Guidance is part of this and will guide all government-promoted retrofits of UK homes.
PAS 2035 is an output of Each Home Counts, an independent review of consumer advice, protection, standards and enforcement for UK home energy efficiency and renewable energy measures, led by former BRE CEO Dr Peter Bonfield. It made 27 recommendations, including establishing a quality mark for domestic retrofit supported by an industry code of conduct, a consumer charter and a framework of technical standards for retrofit. The quality mark has subsequently been established as the TrustMark Government Endorsed Quality Scheme.
PAS 2035 is the over-arching document in the retrofit standards framework, with which users of the TrustMark scheme will be required to comply with when carrying out retrofit on UK homes. All the other standards referred to in PAS 2035 are part of the retrofit standards framework and users of the TrustMark scheme must also comply with those standards, as appropriate. It is expected that PAS 2035 will also be applied to retrofit projects outside the TrustMark quality assurance framework where public finance is involved.
PAS 2035 requirements
PAS 2035 sets out a requirement to properly assess dwellings, design and implement retrofit work. It interfaces with PAS 2030: 2019 Specification for the Installation of Energy Efficiency Measures (EEM), in existing dwellings and insulation in residential park homes, a revision of a previous publication, which has also been recently published. This is the specification for installers to follow when selecting components, and exact methods of installation along with commissioning, including processes and vocational skills, training and qualifications.
The PAS requires a whole house approach. That doesn’t mean that everything in a home must be addressed, but that the planned retrofit must take account of the house or home as a whole, reducing the risk of inadvertently installing measures that negatively impact others. The whole house approach is principally risk-based: projects are categorised in one of three risk-based groups, as determined through the risk matrix.
It starts with the premise that buildings need to be retrofitted in order to improve their energy efficiency rather than a review of priorities for the fabric as a whole, which means proven methods of aiding energy efficiency such as maintenance and appropriate repair are not included, although their attributes are mentioned in side notes.
PAS 2035 splits the enactment of the specification into specific roles. In addition to the duties and responsibilities of the roles, there are specific requirements for the individuals fulfilling the roles to undertake training and possess qualifications and memberships of professional institutions such as the CIOB. These requirements are dependent on the role and the type of building being retrofitted.
The retrofit co-ordinator is the key role, which is basically a project manager with expertise in retrofitting buildings. It is an overarching role with responsibility for co-ordinating and overseeing the activities of the other roles which are all largely self-explanatory: retrofit advisor, retrofit assessor, retrofit designer, retrofit evaluator and retrofit installer.
The tasks to be performed by the retrofit co-ordinator are broad, ranging from working out the technical risks to advising on listed building consent. It is also stated that the retrofit co-ordinator should undertake other roles as necessary, when other individuals in other roles are not appointed. The retrofit co-ordinator is required to obtain a Level 5 Professional Diploma in ‘Domestic Retrofit Coordination and Risk Management’, with training available from the Retrofit Academy.
With over 50 individuals on the PAS 2035 steering group, it is of course difficult to find a consensus on all issues. Despite opposing views, BSI has succeeded in recognising different building types and that traditional buildings need to be treated differently to others.
There is a requirement to follow BS 7913: 2013: Guide to the conservation of historic buildings. This is a standard, applicable to a quarter of UK homes (all homes built prior to 1919) and promotes a holistic approach to energy efficiency. The recently published BSI (British Standards Institution) PAS 2035: 2019: Retrofitting Dwellings for Improved Energy Efficiency – Specification and Guidance is part of this and will guide all government-promoted retrofits of UK homes.
Retrofitting of historic buildings should follow BS 7913: 2013
The retrofit advisor will either be a qualified retrofit co-ordinator or a qualified domestic energy assessor and may also have to hold a CITB Level 3 Award in the Energy Efficiency and Retrofit of Traditional Buildings. This is an established qualification in retrofit, independently accredited by the Scottish Qualification Authority, with training available from the Environment Study Centre in conjunction with CITB.
Some low risk areas are covered, where at the very least a retrofit co-ordinator will be involved. For higher risks, higher ranking professionally qualified designers with membership of a professional institution such as the CIOB is required. Here, where the building is traditionally built, the designer will also need to be a member of a building conservation competency scheme. This doesn’t have to be in the highest membership category; the ‘Registrant’ category of the CIOB Building Conservation Certification scheme would provide the threshold attainment level.
The CIOB scheme is the only building conservation certification scheme which has energy efficiency and sustainability as part of the scheme assessment criteria. For traditional buildings which have special protection, such as listed buildings, the highest level of membership in such a scheme is required. Although not mentioned in PAS 2035, training concerning traditional buildings should be delivered by individuals that are conservation certified.
A good attempt has been made to ensure that individuals are competent, but this is not a requirement in PAS 2035. Some building conservation competency schemes, including the CIOB scheme, may provide a future model for the robustness needed in demonstrating competency in retrofit.
Nevertheless, PAS 2035 should allow for a substantial improvement to the way UK homes are retrofitted. It requires a proper assessment of a building and well-considered proposals and specifications of what works should be carried out. It aims to make the necessary improvements by providing detailed requirements that cover building pathology, thermal modelling and calculations, ventilation, interactions between energy efficiency measures, testing, commissioning, monitoring and evaluation. It also offers very specific technical requirements in relation to ventilation and the calculation of energy loss.
PAS 2035 is only the beginning of the journey involved is developing much improved standards. A review of PAS 2035 will take place in eighteen months and the BSI Retrofit Standards Group have already been looking at broadening the scope. Hopefully maintenance and repair will be part of this but also taking a broader and more detailed look at carbon.
PAS 2030 is also critically important and contains some robust processes that will also contribute to improving quality of work, but again its only the start. Without a sustainable approach to making UK homes more energy efficient the UK will not meet its climate change carbon reduction targets.
Professor John Edwards FCIOB is a director of Edwards Hart Consultants and professor of practice at the University of Wales Trinity St David. He is a member of the BSI PAS 2030 and PAS 2035 steering groups and Retrofit Standards Task Group.