We were commissioned by the Energy Savings Trust to carry out a pilot study for retrofit of two uninsulated houses on the Old Oak Estate in west London. Rather than setting specific performance targets the study had a pragmatic aim of achieving the best performance possible with commonly available building products and trade skills. A budget of £20,000 was set per dwelling to reflect the realm of acceptable expenditure of an owner-occupier.
We carried out surveys of the houses and made proposals for how the existing fabric could be insulated to improve their energy performance. The Old Oak Estate is a conservation area so the fronts of the houses could not be externally insulated but we agreed with the local authority conservation officer that it would be acceptable to externally insulate the rear of the properties. The houses therefore offered a variety of conditions around which we developed working details.
The study was intended as the first step in a process of developing a set of best-practice details for commonly occurring situations that can be easily interpreted, implemented and positively accepted by general builders. The Trust's long term aim is to develop a set of 'vernacular' builders details that enter everyday common use. Our proposals were reviewed and developed over several sessions with a steering group of industry experts.