Limiting thermal bridging and air leakage within a home extension

The building regulations in the UK require that extensions must be constructed so that there are no ‘thermal bridges’, or gaps in the insulation layers within the various elements of the building fabric (i.e. walls, roofs and floors), at the joints between elements or around openings such as windows and doors.

The construction must also include reasonable sealing measures to reduce unwanted air infiltration.

In England and Wales, a way of meeting these requirements is to adopt the ‘robust construction details’ illustrated in Limiting thermal bridging and air leakage: robust construction details for dwellings and similar buildings.