Wall type 2: Cavity masonry

2.61 The resistance to airborne sound depends on the mass per unit area of the leaves and on the degree of isolation achieved. The isolation is affected by connections (such as wall ties and foundations) between the wall leaves and by the cavity width.


2.62 Four wall type 2 constructions (types 2.1, 2.2, 2.3 and 2.4) are described in this guidance.

2.63 Two of these wall constructions (types 2.3 and 2.4) are only suitable when a step in elevation and/or a stagger in plan is incorporated at the separating wall.

2.64 Details of how junctions should be made to limit flanking transmission are also described in this guidance.

2.65 Points to watch


Do not

Wall ties in separating cavity masonry walls

2.66 The wall ties used to connect the leaves of a cavity masonry wall should be tie type A.

Cavity widths in separating cavity masonry walls

2.67 Recommended cavity widths are minimum values.

Blocks with voids

2.68 The guidance describes constructions that use blocks without voids. For blocks with voids, seek advice from the manufacturer.

2.69 Wall type 2.1 Two leaves of dense aggregate concrete block with 50 mm cavity, plaster on both room faces (see Diagram 2-15)

Example of wall type 2.1

The required mass per unit area would be achieved by using

This is an example only. See Annex A for a simplified method of calculating mass per unit area. Alternatively use manufacturer’s actual figures where these are available.

Diagram 2-15: Wall type 2.1
Diagram 2-15: Wall type 2.1 soundproofing

Resistance to the passage of sound 24

prev - Soundproofing For Document E compliance index - next