Plaster and Gypsumboard Construction Terms

Core. The gypsum structure between face and back papers of gypsumboard.
Coreboard. A gypsumboard, usually 24 in wide and up to 1 in thick, with square, rounded or tongue-and-groove edges, and homogeneous or laminated.

Corner Bead. A strip of sheet metal with flanges and a nosing at the junction of
the flanges; used to protect arrises.
Corner Cracks. Cracks in joint of intersecting walls or walls and ceilings.
Corner Floating. (See Floating Angles.)
Cornerite. Reinforcement for plaster at a reentrant corner.
Cornice. A molding, with or without reinforcement.
Cove. A curved concave, or vaulted, surface.
Crown. A buildup of joint compound over a joint to conceal the tape over the joint.
Cure. Treatment, usually of a portland-cement plaster, to ensure hydration after application.
Dado. The lower part of a wall usually separated from the upper by a molding or other device.
Darby. A flat wood tool with handles about 4 in wide and 42 in long; used to smooth or float the brown coat; also used on finish coat to give a preliminary true and even surface.
Dentils. Small rectangular blocks set in a row in the bed mold of a cornice.
Dimple. The depression in the surface of gypsumboard caused by a hammer in setting a nail head slightly below the surface, to permit concealment of the nail with joint compound.
Dope. Additives put in any type of mortar to accelerate or retard set.
Double-up. Applications of plaster in successive operations without a setting and drying interval between coats.
Double Nailing. A method of applying gypsumboard to framing with pairs of nails at intervals of about 12 in along the framing, to ensure firm contact. (The nails in each pair are usually set about 2 in apart.)
Dry out. Soft chalky plaster caused by water evaporating before setting.
Drywall Construction. Application of gypsumboard. (This is basically a dry process rather than a wet process, such as lath and plaster.)
Beveled. The factory-formed edge of gypsumboard that has been sloped so that, where two boards abut, a V-groove joint is created.
Chisel. A slanted factory edge on gypsumboard.
Feathered. A thin edge formed by tapering joint compound at a joint to blend with adjoining gypsumboard surfaces; also denotes the skived edge of joint tape.
Featured. A configuration of the paper-bound edges of gypsumboard that provides special design or performance characteristics.
Floating. An edge that does not lie directly over framing and that will be unsupported after installation of gypsumboard or plaster.
Hard. A special core formulation used along the paper-bound edges of gypsumboard to improve resistance to damage during handling and application of the board.
Skive. The outside edges of joint tape that have been sanded or chamfered to improve adhesion and reduce waviness.

Tapered. A factory edge on gypsumboard that is progressively reduced in thickness to allow for concealment of joint tape below the plane of the gypsumboard surface.
Efflorescence. White fleecy deposit on the face of plastered walls, caused by salts in the sand or backing; also referred to as whiskering or saltpetering.
Egg and Dart. Ornamentation used in cornices consisting of an oval and a dart alternately.
Eggshelling. Plaster chip-cracked concave to the surface, the bond being partly destroyed.
Enrichments. Any cast ornament that cannot be executed by a running mold.
Expanded Metals. Sheets of metal that are slit and drawn out to form diamondshaped openings.
Fat. Material accumulated on a trowel during the finishing operation of plaster and used to fill in small imperfections. Also denotes a mortar that is not too stiff, too watery, or oversanded.
Feather Edge. A beveled-edge wood tool used to straighten reentrant angles in the finish plaster coat.
Fines. Aggregate capable of passing through a No. 200 sieve.
Finish Coat. Last and final coat of plaster; also denotes a thin coat of joint treatment to reduce variations in surface texture and suction.
Finisher. A tradesman with skill in finishing of gypsumboard joints.
Fire Taping. Taping of gypsumboard joints without subsequent finishing coats, usually used where esthetics is not important.
Fisheyes. Spots in plaster finish coat about 1⁄4 in in diameter, caused by lumpy lime because of age or insufficient blending of material.
Float. A tool shaped like a trowel, with a handle braced at both ends and wood base for blade, used to straighten, level, and texture finish plaster coats.
Floating Angles (Corner Floating). Unrestrained surfaces intersecting at about 90, usually with fasteners omitted near the intersection (Fig. 11.28).
Foil Back. A gypsumboard with a reflective aluminum-foil composite laminated to its back surface.
Furring. Strips that are nailed over studs, joists, rafters, or masonry to support lath or gypsumboard. This construction permits free circulation of air behind the plaster or gypsumboard.
Gaging. Mixing of gaging plaster with lime putty to acquire the proper setting time and initial strength. Also denotes type of plaster used for mixing with the putty.
Green Board. A gypsumboard with a tinted face paper, usually light green or blue, to distinguish special types of board; also denotes gypsumboard that is damp.
Green Plaster. Wet or damp plaster.
Grounds. A piece of wood, metal, or plaster attached to the framing to indicate the thickness of plaster to be applied.
Gypsum. Fully hydrated calcium sulfate (calcium sulfate dihydrate).
Gypsum Base. Gypsum lath used as a base for veneer plasters.

Gypsumboard. A noncombustible board with gypsum core enclosed in tough, smooth paper.
Type X. A gypsumboard specially formulated with high fire resistance for use in fire-rated assemblies.
Hardwall. Gypsum neat base-coat plaster.

Scroll to Top