Insulation stops heat escaping by blocking conduction. But it can’t do its job properly if heat is also being carried away by unwanted air movement. Kate de Selincourt talked to Mark Siddall and asked him to explain how thermal bypass may undermine building performance – and what we can do to prevent it.

From concept to handover, we describe what needs to happen at every RIBA stage for a successful airtightness test.

When it comes to vapour checks, there are some myths that are passed on from generation to generation. One myth is that there is an urgent need for a vapour barrier.