Wall plaster takes varying lengths of time to dry and completely cure. The average drying time for a centrally heated room is four to six weeks before the plaster can be painted or papered, but the wait can be months in some cases.
Drying time can be shortened to about three weeks by applying more heat to a room to aid in water evaporation from the plaster. However, it may take several months for plaster to cure completely. Plaster must always be allowed to dry before it is covered with another material. Otherwise, the new material can trap water inside the plaster, and mold may result.