Support plaster is a type of plaster used in construction to provide support and stability to walls and ceilings. It is made up of a mixture of cement, sand, and water, and is applied in thin layers to the surface of the wall or ceiling. The term 'LATH' refers to a thin strip of wood or metal that is used to provide a base for the plaster. LATH is typically nailed to the wall or ceiling before the plaster is applied.