This British Standard gives recommendations for the design of joints and the use of jointing products in building construction. Following an analysis of joint functions and of the performance of the parts to be joined, joints are classified in this standard on the basis of the movements and inaccuracies they have to accommodate. Mechanisms by which joints operate are identified and recommendations are made on the use of sealants and gaskets. Some emphasis is placed on weather resistance of joints in the external envelope of buildings.