Technical Booklet G Resistance to the Passage of Sound·Page 36·2.40
External cavity wall - cavity closure requirement
When the external wall is a cavity wall, the outer leaf can be any construction, but the cavity must be closed with a cavity stop as shown in Diagram 2.9.
Where the external wall is a cavity wall –
(a) the outer leaf of the wall may be of any construction; and
(b) the cavity should be closed with a cavity stop (see Diagram 2.9).
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