Plaster that surrounds, penetrates, or deforms to lock onto the perforations of a plaster base is called what?

Plaster that surrounds, penetrates, or deforms to lock onto the perforations of a plaster base is called what?

• A. Key
• B. Base
• C. Screed
• D. Lath

Answer: (A)

Keying creates a mechanical bond between plaster and its base. When plaster is applied over a perforated lath or rough base, it flows into the holes and around the irregularities, hardening into a “key” that locks the plaster in place and resists pulling away. This interlock is what the term refers to. The base is the underlying surface, the lath is the supporting framework, and screed is a leveling layer—none of these describe the locking action as directly as the key does.

Keying creates a mechanical bond between plaster and its base. When plaster is applied over a perforated lath or rough base, it flows into the holes and around the irregularities, hardening into a “key” that locks the plaster in place and resists pulling away. This interlock is what the term refers to. The base is the underlying surface, the lath is the supporting framework, and screed is a leveling layer—none of these describe the locking action as directly as the key does.