There is currently a demand for buildings that can be formed both quickly and economically. These buildings require the addition of heat insulation to walls or roofs because the materials from which they are otherwise formed have insufficient ability to protect against the cold. This can add undesirable expense and slow down production rates. A method is disclosed of forming a building that addresses this problem. The method comprises arranging a door frame, window frame or edge support frame at a mould and spraying a first spray material onto the outside of the mould so that the spray material sets generally in the shape of the mould and substantially embeds the frame. The first material and the frame is removed from the mould and a second different spray material is sprayed onto the first spray material to provide a skin therefor.