§ Mr. Normantonasked the Secretary of State for the Environment, in view of confusion in the minds of house owners as to the legality and effectiveness of cavity wall insulation, whether he will give advice on these questions, in the interests of energy conservation, to the insulation industry and the public generally.
§ Mr. FreesonAs has been made clear in the Department's advisory pamphlets "Warmth Kept In" and "Warmth Without Waste", cavity wall insulation is generally a useful way of improving the thermal insulation of buildings. If not done properly, however, or if applied to buildings exposed to severe driving rain, it can lead to damp penetration. For this reason, a relaxation of Building Regulation C9(2), designed to prevent damp in cavity walls, must be obtained before such work is carried out. A circular letter was sent to local building control authorities on 29th April outlining the circumstances in which it was considered that they might relax the 515W regulation. In the Department's view, relaxation should be permissible in the great majority of cases.