2.2 : Masonry Cavity Walls

A masonry cavity wall consists of two wythes separated by a hollow space. The outer and inner wythes are connected using corrosion-resistant masonry ties for structural stability.

When water penetrates the outer wythe, it enters the cavity and is collected by a thin impervious membrane called flashing, which is installed at the cavity's bottom and drained out through weep holes.

Additionally, dampproofing material applied on the cavity side of the inner wythe will protect the interiors from water penetration and also serve as an air barrier.

During construction, debris like mortar droppings can block the drainage system, making it crucial to keep the cavity clear. Using mortar deflection material can help avoid blockage of drainage in the cavity.

The cavity facilitates sound insulation and the placement of conduits for utility distribution within a building.

Also, inserting insulating boards of rigid foam plastic in the cavity can provide thermal insulation.

Cavity walls can be load-bearing or non-load-bearing. In load-bearing cavity walls, the inner wythe supports structural loads, while the nonstructural outer wythe is a veneer.

In non-load-bearing walls, the inner wythe provides lateral support to the outer wythe through the masonry ties.