Wall Type 4 – Framed Walls with Absorbent Material: General Guidance

In this guidance only a timber framed wall is described. For steel framed walls, seek advice from the manufacturer. The resistance to airborne sound depends on the mass per unit area of the leaves, the isolation of the frames, and the absorption in the cavity between the frames. The construction consists of timber frames, with plasterboard linings on room surfaces and with absorbent material between the frames. One wall type 4 construction (type 4.1) is described in this guidance. Details of how junctions should be made to limit flanking transmission are also described in this guidance.