Metal lathing forms a convenient base for plaster in some types of construction, but if subsequent defects are to be avoided appropriate mixes and methods of fixing must be used. Reports received at the Building Research Station indicate that the most common defects found in plaster on metal lathing are extensive cracking, particularly along the line of fixing of the lathing to its supports, or unevenness of the finished plaster surface, or of shelling of the finishing coat from the undercoat, or combinations of these. Methods of avoiding defects are described.