External cavity wall construction components

The construction of external cavity walls could include – (a) an outer leaf of masonry (bricks, blocks, stone or manufactured stone); (b) a cavity at least 50 mm wide. The cavity is to be bridged only by wall ties, cavity trays provided to prevent moisture being carried to the inner leaf, pipes and ducts, cavity insulation (see paragraphs 6.16 and 6.17), cavity barriers, firestops and cavity closures, where appropriate; and (c) an inner leaf of masonry or frame with lining. Masonry units should be laid on a full bed of mortar with all joints substantially and continuously filled to ensure weather resistance. Where a cavity is to be partially filled, the residual cavity should not be less than 50 mm wide (see Diagram 6.4(c)).