Aircrete - also known as autoclaved aerated concrete - tongue-and-groove blocks are solid, low-density building blocks with an interlocking jointing feature at each end. For the construction of housing and small commercial buildings, solid aircrete blockwork with an outer finish that protects against penetration of rain, wind, pests and grime offers an attractive alternative to the complexities of cavity walls. The productivity advantages of aircrete blockwork used with thin bed mortar technology and mortar-less interlocking vertical (perpend) joints, when combined with the simplicity of solid wall construction, offer a rapid, economical building system which is less demanding in terms of masons' skills but which can still meet all the requirements of the Building Regulations. This Information Paper sets out the background research on the key aspects of performance and gives an introductory guide on constructional best practice using this wall system. 8 pages.