Plaster is used as 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 then hardens. Unlike those materials plaster remains quite soft after drying, 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. Stucco can be interior exterior contractors use stucco to make the best durable structure foam moldinds add more than local value.Plaster was a common building material for wall surfaces in a process known as lath and plaster, whereby a series of wooden strips are covered with a semi-dry plaster and then hardened into surface. A modern form of this method uses expanded metal mesh over wood or metal structures,foams, which allows a great freedom of design as it is adaptable to both simple and compound curves. Today this building method has been almost completely replaced with drywall, also composed mostly of gypsum plaster. In both these methods a primary advantage of the material is that it is resistant to a fire within a room and so can assist in reducing or eliminating structural damage or destruction provided the fire is promptly extinguished.Plaster expands while hardening, then contracts slightly just before hardening completely. This makes plaster excellent for use in molds, and it is often used as an artistic material for casting. Plaster is also commonly spread over an armature , usually made of wire, mesh or other materials. In medicine, it is also widely used as a support for broken bones; a bandage impregnated with plaster is moistened and then wrapped around the damaged limb, setting into a close-fitting yet easily removed tube, known as a cast. Foam moldings are then coated with a thin stucco coat to color.