Plaster is a building material similar to mortar or cement. Like those materials, plaster starts as a dry powder that is mixed with water to form a paste which liberates heat and then hardens. Unlike mortar and cement, plaster remains quite soft after setting, and can be easily manipulated with metal tools or even sandpaper. These characteristics make plaster suitable for a finishing, rather than a load-bearing material.

The term plaster can refer to gypsum plaster (also known as plaster of Paris), lime plaster, or cement plaster.

Gypsum-based plaster used in spray fireproofing in a low-rise industrial building in Vancouver, British Columbia.

 

From Wikipedia, the free encyclopedia : Manufacture of plaster products for construction