G. J. EDGELL*, R. C. DE VEKEY** and R. DUKES* *British Ceramic Research Limited **Building Research Establishment

Storey height and half-storey height walls, wallettes and stack bonded prisms were built in one of seven bricks, four blocks and three mortars. Parameters examined were format, capping method, curing method, platen and machine stiffness and joint thickness. Mortar capping provided the highest compressive strengths with reasonable C.V. Block work wallettes confirmed 1.5 blocks wide by 3 courses high as the appropriate format. Close covering for 3 d followed by curing in laboratory air was found suitable. Relationships between strengths of various wallette formats and between them and the walls and the influence of mortar designations were established. The mean ratio of wall/wallette strength is 0-875 showing that for axially loaded slender walls the formula in EC6 and table in BS 5628 are very conservative.