From Longman Dictionary of Contemporary Englishcavity wallˈcavity ˌwall noun [countable] TBCa wall consisting of two walls with a space between them to keep out cold and noise cavity wall insulation
Examples from the Corpus
cavity wall• If you plan to have cavity wall insulation installed, start by approaching your local authority Building control Officer for approval.• Incidentally, cavity wall insulation should be impermeable to water vapour, or interstitial condensation can occur.• The work will include cavity wall insulation, roof insulation, double glazing and installation of energy efficient heating systems.• As well as these weather-resisting advantages, the cavity wall has greater sound and thermal insulating properties and a greater resistance to overturning.• His head jerked and banged against the cavity wall, then it did it again and after that, a third time.• Other parts of the treatment involved the cavity wall ducts under the building and some internal work in the flats. 