Glossary of Terms


An admixture that speeds the rate of hydration of hydraulic cement shortens the normal time of setting or increases the rate of hardening, of strength development, or both, of Portland cement plaster.


A substance that is interground or blended in limited amounts into a hydraulic cement during manufacture - not at the job site - either as a processing addition to aid in manufacturing and handling the cement or as a functional addition to modify the useful properties of the cement.


A material other than water, aggregate, or basic cementitious material added to the batch before or during job mixing.


A granular material such as natural sand, vermiculite or perlite.

American Plywood Association

An association focused on assisting the industry in creating structural wood products of exceptional strength, versatility and reliability as well as promoting suggestions and solutions to benefit the industry.


The accumulation of mixing water on the surface of plaster caused by compression of the solid materials within the mass. Bleed water occurs on the surface of a mass of plaster in a container or hopper, commonly influenced by vibration. Also called water gain.

Blended Hydraulic Cement

A binder produced by intimately and uniformly intergrinding or blending two or more types of fine materials, such as Portland Cement, ground granulated blast-furnace slag, fly ash, silica fume, calcined clay, other pozzolans and hydrate lime.


The bubbling of the finish plaster coat where it separates and expands away from the base coat.


Adhesion of stucco to other surfaces against which it is applied; adhesion of cement paste to aggregate; adhesion between stucco coats or between stucco and a substrate


A material used to prevent adhesion of newly placed plaster to a section of the substrate.

Bond Strength

The adhesion developed between stucco and a substrate; the resistance to separation of plaster from other materials in contact with it.

Bonding Agent

A compound applied as a coating to a suitable substrate to enhance a bond between it and a succeeding layer, as between a subsurface and a succeeding stucco application.

Building Structure

A wall assembly consisting of wood or steel studs with a sheathing board.


Reaction between carbon dioxide and a hydroxide to form a carbonate, especially in cement paste or plaster; the reaction with calcium compounds that produces calcium carbonate.


Blemishes or rough depressions in finish stucco comparable to pockmarks.

Cementitious Material

A material that, when mixed with water and with or without aggregate, provides the plasticity and the cohesive and adhesive properties necessary for placement and the formation of a rigid mass.


Development of shallow cracks at closely spaced but irregular intervals in the stucco surface.


A thickness of stucco applied in a single operation.


The ability of a material to cling to itself.


The relative mobility or ability of freshly mixed plaster to flow.

Cold Joint

The juncture of fresh stucco application adjacent to set plaster.

Control Joint

Generally refers to a flexible, single piece component designed to control the thermal and normal shrinkage in cement plaster.

Corner Reinforcement (corner bead)

Reinforcement for stucco used at corners to provide continuity between two intersecting stucco planes.


Disintegration or deterioration of metal reinforcement due to electrolysis or chemical attack.


Keeping freshly applied stucco moist and at a favorable temperature for a specified period of time following the application. Curing assures satisfactory hydration and carbonation of the cementitious materials and proper hardening of the stucco.


The distortion or warping of an essentially planar surface into a curved shape, due to several factors such as temperature and moisture differences within the stucco coat.


Treatment of plaster to retard the passage or absorption of water, or water vapor, either by application of a suitable surface treatment on exposed surfaces or by use of a suitable admixture or treated cement.


A flat wooden or metal tool approximately 4 inches wide and 42 inches long with handles used to level out the brown coat.

Dash-bond Coat

A thick wet mixture of portland cement and water, with or without aggregate, dashed onto the surface of stucco base, such as smooth monolithic concrete or concrete blocks, to improve the mechanical key for subsequent stucco coats.

Dash Finish

A final texture that is usually machine applied. The texture will vary depending the type of machine, air pressure, size of nozzle and aggregate.


Change in color from the normal or desired hue.


The ability of Portland Cement plaster to resist weathering action, chemical attack, abrasion and other potentially harmful service conditions.


A chalky or powdery white film that forms on or below the surface of cementitious types of materials such as concrete, brick and stucco, resulting from the deposit of water-soluble mineral salts. These salts can migrate to the surface in diverse ways, most significant by water, which leaves the salt deposits after evaporation.

Elastomeric Coating

A material that can expand and contract without rupture, based on its elongation properties.

Expanded Metal Lath

Sheets of metal that are slit and pulled out to form diamond-shaped openings; used as metal reinforcement for plaster.

Expansion Joint

Generally refers to a telescoping two or three-piece accessory designed to control structural or seismic stresses.

Exterior Insulation and Finishing System (EIFS)

Proprietary cladding system incorporating an insulation board, lamina and an acrylic finish coat.

Factory Prepared Stucco Materials ("mill-mixed" or "ready-mixed")

Pertaining to material combinations that have been formulated and dry-blended by the manufacturer, requiring only the addition of and mixing with water to produce stucco. (Stucco finish coat)

Faux Finish

Generally refers to a painted surface made to imitate a variegated plaster finish (French).


A wood or metal tool with a beveled edge and varying in length; used to straighten reentrant angles in finish-coat plaster. Also used to plane the surface of the brown coat and dry rod or dry rake it to better control color in the finish coat.

Fine Aggregate

Natural or manufactured sand that passes the No. 4 (4.75-mm) sieve.

Finish Coat

The final coat of stucco, referred to as the decorative surface, usually colored and textured.


A metal or self-adhered flashing tape material used to prevent water entry and/or direct the water migration in a desired direction between two or more materials and/or surfaces.


Act of compacting and leveling a stucco basecoat; act of bringing the aggregate to the surface of finish-coat stucco.

Fog Coat

A fine mist of cement based paint color used to provide uniformity in integral colored cement finish coats.


Structural members such as columns, beams, girders, studs, joists, headers, trusses, etc., of wood or steel.


The size distribution of aggregate particles, determined by separation with standard screen sizes.

Hairline Cracks

Very fine cracks in either random or essentially straight line patterns that are just visible to the naked eye.

Harsh Mixture

A mixture that lacks desired consistency and workability due to a deficiency of cement paste, aggregate fines, sufficient water or a combination of the above.


A tool to hold and carry plaster from the board to the working face during hand-applied plastering.

Hydrated Lime

The product manufactured by heating limestone until carbon dioxide is removed, thus forming quicklime (calcium and magnesium oxides), subsequently hydrated using water additions. Hydrated lime processing involves pressure hydration, atmospheric hydration, or slaking.

Lace Finish

Refers to a lighter skip trowel finish than Spanish texture.


Reinforcement base to receive plaster, generally secured to a substrate.

Live Crack

The process of a crack still opening. Generally related to structural or substrate movement or expansion.

Mechanical Bond

The physical keying of one plaster coat to a substrate or another coat; or plaster keying to metal lath; or interlock between adjacent plaster coats created by surface irregularities, such as scratching.

Metal Lath

The slit and expanded or stamp-punched from plain or galvanized steel coils or sheets that are coated with a rust-inhibiting paint after fabrication or is galvanized.

Moisture Movement

The migration of moisture within and from a porous medium, caused by an imbalance as surface moisture is lost through evaporation.


Attachment at discharge end of delivery hose used for machine application of plaster. The nozzle allows adjustment of the spray pattern.

One-Coat Stucco

A proprietary cladding system, consisting of lath, one basecoat and a finish coat.


A cementitious material or combination of cementitious materials and aggregates that, when mixed with water, creates a workable material which hardens to a rigid state.

Plaster Ground

A piece of wood or trim accessory that acts as a termination and/or gauge to determine the thickness of the plaster.


A complex property of plaster involving the flow of the plaster associated with an applied force; that property of freshly mixed plaster that determines its resistance to deformation or its ease of molding.


Poly Vinyl Chloride. Plastic that is used to manufacture stucco trim.


The build-up of material in a specific area.

Rain Screen

Generally refers to an exterior wall cladding system with a measurable airspace between the building sheathing material and the backside of the exterior cladding system.

Reentrant Crack

A hairline crack that can develop at the apex of a 90° corner in Portland Cement products.


Slowing down the rate of hardening or setting of plaster to increase the plaster setting and hardening times.


After initial mixing, adding water and remixing plaster that has started to stiffen and become harsh.


A straight edge used in plastering to straighten walls and ceilings, typically constructed of magnesium or aluminum.


A method of straightening the stucco basecoat.


Lath manufactured to include raised portions of the lath, ribs, or dimples that hold the lath away from the supporting surface and position it for embedment with stucco.


The change in plaster from a plastic, workable state to a solid, rigid state. Set is modified by the terms "initial" and "final," both arbitrary appraisals of degree of hardening.

Skim Coat

A finish coat applied to an existing stucco surface or other substrate to improve appearance.


Similar to Checking, but the bond has been partially or fully damaged.

Spanish Texture

Refers to a medium to heavy skip-trowel finish coat.

Stucco Finish Coat

The final layer of stucco (job-site mixed or pre-manufactured) applied over basecoat stucco or direct to concrete.


Referring to the surface to which lath and plaster is to be applied.


The absorptive capacity of a substrate or stucco surface.


A flat, broad-blade steel hand tool used to apply, spread, shape and smooth finish-coat plaster.

Vapor Permeable

A material that will allow water to pass through as a gas (vapor).


Finished surface which is irregularly marked with different colors.


A deviation of a wall surface from its original shape, usually caused by temperature or moisture differentials within the plaster.

Weather Resistant Barrier

A material behind an exterior wall covering that is intended to resist liquid water that has penetrated behind the exterior covering from further intruding into the exterior wall assembly.


The property of freshly mixed stucco that determines its working characteristics, i.e., the ease with which it can be mixed, placed, and finished.

Zinc Alloy

A soft malleable bluish-white metal.