Lessons learnt by the first four developers to design and build to the Code for Sustainable Homes on the BRE Innovation Park have led to the compilation of detailed guidance in a BRE Information paper entitled Applying the Code for Sustainable Homes on the BRE Innovation Park.
Devised to help UK housebuilders deliver code compliant homes, the guidance is now being published in four-parts covering the following key areas: building fabric, energy and ventilation, water, and architecture, construction and sourcing. Part 1 of the Information Paper, Lessons Learnt About Building Fabric has just been published.
The lessons learnt are based on the experiences of companies - EcoTech, Hanson, Kingspan Offsite and Stewart Milne Group who put their reputations on the line as the first companies to design and build to the Code between November 2006 when the Code was published and the BRE Offsite07 exhibition in June 2007.
Experience gained at the Innovation Park shows that simple house designs are easier to make airtight, as are large panel construction systems with few joints. ‘When approaching airtight house design it's wise to recognise the difficulty of achieving low permeability on site, and take this into account at the planning stage,' says Chris Gaze, the Information Paper's author. ‘The aim should be to make the whole house airtight with a robust primary air barrier.'
‘The Code for Sustainable Homes is accelerating changes in how a building's fabric is constructed for thermal insulation and airtightness, and to avoid thermal bridging,' says Gaze. ‘The building elements used in the four demonstration houses, for example, were all of a high thermal specification. Minimising thermal bridging was also critical to their success, as was achieving good airtightness - one of the most challenging parts of the Code.'
Windows and doors must be specified and installed for airtightness along with daylighting and solar gain, thermal performance and sustainability. ‘Sustainably sourced windows and doors with low U-values that are also Secured by Design approved are available,' says Gaze. ‘For these projects they were all sourced from outside the UK, but UK fenestration suppliers are catching up.'
Full details on this publication are available from http://www.brebookshop.com/. The following three parts of the Information paper will shortly be available:
- Part 2 - Lessons learnt about energy sources, overheating and ventilation (September)
- Part 3 - Lessons learnt about water use, harvesting, recycling and drainage (October)
- Part 4 - Lessons learnt about architecture, construction and sourcing (November