Cavity-wall insulation falls into two categories, based upon whether the insulation partially fills the width of the cavity (partial-fill) or completely fills the full width of the cavity (full-fill). The choice of insulation method depends on the nature of the materials that are selected to construct and insulate the cavity wall in order to meet the thermal insulation requirements of the current Building Regulations. From a bricklayer’s point of view, the choice of insulation method is an important consideration as it determines the manner in which the cavity wall is constructed.