Absorption. The rate of absorption of water into gypsumboard, as determined by the test described in ASTM C473.
Accelerator. Any material added to gypsum plaster that speeds the set.
Acoustical Plaster. A finishing plaster that corrects sound reverberations or reduces noise intensity.
Adhesive Spreader. A notched trowel or special tool that aids in application of laminating adhesives.
Adhesive Wall Clips. Special clips or nails with large, perforated bases for mastic application to a firm surface.
Contact. An adhesive that forms a strong, instantaneous bond between two plies of gypsumboard when the two surfaces are brought together.
Laminating. An adhesive that forms a slowly developing bond between two plies of gypsumboard or between masonry or concrete and gypsumboard.
Stud. An adhesive suitable for attaching gypsumboard to framing.
Admixture. Any substance added to a plaster component or plaster mortar to alter its properties. (See also Dope.)
Arris. A sharp edge forming an external corner at the junction of two surfaces.
Back Blocking. Support provided for gypsumboard butt joints that fall between framing members.
Back Clip. A clip attached to the back of gypsumboard and designed to fit into slots in framing to hold the board in place. Used for demountable partitions.
Back Plastering. Application of plaster to one face of a lath system after application and hardening of plaster applied to the opposite face (used for solid plaster partitions and curtain walls).
Backing (Backer) Board. A type of gypsumboard intended to serve as a base layer in a multilayer gypsumboard system or for application with adhesive of acoustical tile or panels.
Band. A flat molding.
Banjo Taper. A mechanical device that dispenses tape and taping compound simultaneously.
Base (Baseboard). A plastic, wood, or metal trim or molding applied to a wall at the floor line to protect the wall from damage.
Base Coat. The plaster coat or combination of coats applied before the finish coat.
Batten. A predecorated strip or joint covering used to conceal the junction between two boards. It is often used with demountable systems.
Bead. A strip of sheet metal usually with a projecting nosing, to establish plaster grounds, and two perforated or expanded flanges, for attachment to the plaster base, for use at the perimeter of a plaster membrane as a stop or at projecting angles to define and reinforce the edge.
Beaded Molding. A cast plaster string of beads set in a molding or cornice.
Beading. (See Ridging.)