Roadblocks to 2013 improvements and achieving Zero Carbon (Part 3)
There have been arguments to bring parts of the Code for Sustainable Homes into regulations and to then withdraw the Code completely, with suggested substantial cost savings and no significant impact on outcomes.
The Code represents a methodology for going beyond regulations – giving a recognised methodology to show a development as achieving a greater level of sustainability. Withdrawing the Code could result in different Local Authorities coming out with wildly differing local requirements, with developers bewildered as to how to comply from one area to the next. That said, perhaps a simplified optional version akin to Scottish regulations Section 7 (Sustainability) might be worth pursuing for local authority target setting purposes, with the full Code for Sustainable Homes retained for those wanting to receive acknowledgement for having gone further.
Thermal bridging details and the Accredited Construction Details (ACD’s).
There are a couple of issues here. The requirements from the 2010 regulations have been scaled back as there was little or no agreement across industry and Government as to how best to make a full ACD scheme work, whilst at the same time achieving the Government’s intention of reducing red tape. Instead the previously suggested idea for a scheme could form part of the larger quality assurance or PAS suggestions relating to closing any perceived gap between designed and as built.
Audit requirements for as-built dwellings / EPC’s are already tightening to require evidence of sign-off of checklists and process sequences for dwellings built in accordance with the ACD’s – which is a good step. However the whole issue requires better understanding across those involved, from those detailing at design stage, to those building, those assessing, right through to Building Control actually checking that what is detailed is built.
The ACD’s generic psi values for junctions are (in my opinion) no longer fit for purpose and in urgent need of a full re-working in order to provide a robust back drop against which industry can then produce and circulate improved details if they wish to do so. The values in SAP Appendix K for the ACD’s do not differentiate for differing constructions and are based on fabric performance specifications typical at the time of their production. With lower U-values the achieved Psi values for junctions are less likely to be applicable.
I’m not saying drop them – but they definitely need updating.
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