Masonry comprises the parts of a building, mainly the walls, which are constructed using blocks of materials set in mortar, and includes stonework, brickwork and blockwork. Masonry suffers some structural movement due to moisture content and temperature changes, as described in sections 2.3 and 3.5, and it may be necessary to incorporate vertical movement joints to accommodate horizontal movement. Where the masonry forms an external weather protection to a structure of a different nature such as a timber, concrete or steel frame, horizontal movement joints may also be necessary to accommodate differential vertical movement.