Plaster is a building material used for the protective or decorative coating of walls and ceilings and for moulding and casting decorative elements.”Plaster” usually means a material used for the interiors of buildings, while “render” commonly refers to external applications.

The most common types of plaster mainly contain either gypsum, lime, or cement, but all work in a similar way.

The plaster is manufactured as a dry powder and is mixed with water to form a stiff but workable paste immediately before it is applied to the surface. The reaction with water liberates heat through crystallization and the hydrated plaster then hardens.