ABSTRACT
This chapter explains the principles of external masonry wall construction and traces the introduction and evolution of the modern masonry cavity wall. The external walls of a house wall have two basic functions: to transfer the loads from suspended floors and the roof to the foundations and environmental protection. In order to satisfactorily fulfil these functions there are a number of requirements for an external wall. These are: strength and stability, protection against damp and precipitation ingress, effective thermal insulation, fire protection, and durability. Up until the 16th century timber was the dominant structural material for most vernacular buildings. Brick and stone started to be adopted more commonly for a number of reasons. The cheapest type of stone wall was that constructed in a pattern known as random rubble which is where stones of random shape and size are laid in a lime or cement mortar.
