ABSTRACT
The majority of construction materials are supplied to metric dimensions; however, a few materials retain their imperial designations. The range of metal-coated steels includes traditional hot-dip galvanized steel, aluminium-zinc alloy-coated and terne-coated steels. The durability of zinc-coated steel is dependent on the thickness of the coating and the environment, also the avoidance of contact with other metals particularly copper, and the alkalis in wet mortar and plaster. The wide range of products manufactured from wood includes laminated timber, cross-laminated timber, laminated veneer lumber, plywood, particleboard, fibreboard and modified wood. The choice of roofing materials is related to a combination of cost, durability and particularly aesthetics. Many roofing materials such as asphalt are available only in neutral colours, but single-layer PVC, for example, is available in a range of colours. Metal roofing systems give visual articulation, and the choice of the particular metal or coated metal determines both the initial and weathered finish.
