Wall coating is a term used to describe the materials used to cover the interior and exterior of walls. STUCCO, PLASTER, and PAINT are all common wall coatings. STUCCO is a type of PLASTER made from cement, sand, and lime that is applied in multiple layers to create a durable finish. PLASTER is a mixture of lime, sand, and water that is applied in thin layers to create a smooth finish. PAINT is a liquid coating that is applied to walls to create a decorative finish.