J. R. SOUTHERN and C. M. STIRLING Building Research Establishment, Scottish Laboratory.


Walls of different masonry materials facing from ESE through S to WSW were insulated internally between battens and provided with a vapour check. Condensation was deposited on the back of the vapour check and in some of the walls was present throughout most of the summer. Most condensation formed in the SSE facing walls and least in the ESE wall. Less condensation was present in walls built of low than high water absorption bricks. No condensation was seen where a ventilated cavity was present between the insulation and the masonry. High moisture contents were measured in the timber framing at the end of the summer. A method of checking for the condensation is referred to. Methods for reducing the risk of condensation by ventilation within the wall thickness or providing heat to warm the vapour check are briefly discussed.