GOOD HOME ALLIANCE CALLS FOR THE REVIEW OF THE GREEN GUIDE

The Green Guide used in the Code for Sustainable Homes to rate the sustainability of building materials, could actually worsen the overall environmental impact of our buildings. The Good Homes Alliance (GHA), a group of sustainable developers and building professionals who are fully committed to improving the sustainability of new homes, and whose developer members are required to build homes to higher levels of the Government’s Code, has produced a full and detailed critique of the Green Guide and is now calling for the Guide’s urgent review.

Flaws in the methodology and overall structure of the Green Guide have resulted in an inadequate assessment of building materials and systems. This will undermine good design, discourage innovation and improvement in building systems and materials, and provide a barrier to SMEs working in the environmental products sector and to the importation of ecological building systems.

The Green Guide also lacks transparency in method and data. It is therefore not possible to determine what has been included in or excluded from the analysis and therefore to check for errors or properly challenge the results. The lack of transparency will hinder the learning process in the design and construction industries and continue the de-skilling of the industry through the use of a tick box approach to sustainability.

Among the Guide’s biggest defects is the attempt to provide ratings for whole construction build-ups. This method requires so many assumptions to be made and so many complex issues to be over-simplified that the results are not only meaningless, but actually inhibit informed design and the environmental improvement of materials or systems. The division of the ratings into 6 categories from A+ to E tells users nothing of the actual environmental impact of the build-ups. For example, within cavity wall or timber framed and light steel frame construction build-ups under the Rendered or Fairface Blockwork category, every single listed construction achieves an A+ rating. Consequently, there is no way of understanding which systems are better than others or what products within each system have the worst impact and there is no incentive for anyone to innovate or change.

Another flaw in the methodology is that it confuses performance criteria with embodied impact, once again resulting in inappropriate material selection and poor building performance. For example, the Green Guide promotes the use of timber floors (A+ rated) instead of concrete floors (C rated) in domestic buildings, presumably because of the greater environmental impact of concrete. However, in multi-storey apartments and many low-carbon buildings, concrete floors may be necessary structurally, and are often used to prevent overheating and to provide acoustic protection. The effect of specifying timber floors may therefore lead to an increased environmental impact over the life of the building, because the building performance is compromised.

Neil May, Chairman of the Good Homes Alliance, comments: “Flaws in the Green Guide are undermining good building design and could lead to a worsening performance of buildings. What’s more, the Green Guide’s defects are preventing industry professionals from learning about the real environmental impact of building materials and providing the feedback necessary to the transformation of the construction sector. The Green Guide will also discourage innovation in environmental building products and systems.

“While there is a pressing need to assess the environmental impact of building materials as part of the drive to improve the sustainability of our homes, this should be undertaken in a thorough, transparent and simple way. Our critique of the Green Guide has been endorsed by other experts in this field including Dr Fionn Stevenson of Oxford Brookes University and the AECB and we have not come across a single informed professional who is willing to defend the Guide as it now stands. An immediate review of the Green Guide and its use in the Code for Sustainable Homes and in Planning Guidance is necessary. We have raised this issue with CLG and other Government Departments, who have agreed to examine the details further, and we will continue to work with them to ensure the best solution is reached.”

Email: l.marshall@wriglesworth.com