Technical Note #17 Cavity wall construction

The insulation of external masonry walling in the RSA buildings is not mandatory in terms of the National Building Regulations. This Technical Note details the requirements for walling in terms of Regulation XA and SANS10400XA.

Thermal insulation or thermal resistance is achieved by means of three different mechanisms of attenuation of heat transfer: these define the three types of thermal insulation: resistive, reflective and capacitive, two of which are commonly present in insulated masonry wall assemblies. The third, reflective insulation, is often used in low mass (timber or light steel frame) walling constructions