General Terminology Relative to Gypsum Panels
The following terms and definitions appear in Gypsum Association publications. The associated publication(s) is/are listed in parentheses after the definition. These terms and definitions are featured here to facilitate the use of industry vernacular among all stakeholders.
Accessories– Control joints, corner reinforcement trim, or molding used to protect or conceal corners, edges, wall terminations, or abutments of the gypsum panel (GA-214).
Base Layer – The first layer of gypsum panel products applied in a multi-layer application (GA-216).
Control Joint – A designed and installed separation between adjacent gypsum panels and their supporting framing members to relieve stresses caused by expansion and contraction of materials, resulting from humidity and temperature changes in the environment (GA-216).
Critical Lighting – Strong side lighting from windows or surface-mounted light fixtures. syn severe lighting (GA-214).
Edge – A bound edge as manufactured (GA-216, GA-253).
End (Butt) – A mill-cut or field-cut end perpendicular to the edge. At such cuts the gypsum core is exposed (GA-216, GA-253).
Expansion Joint – A structural separation through a building assembly that provides movement relief of the building in any plane (GA-216).
Exterior Cladding – A permanent material or system that impedes the transmission of environmental elements to the sheathing (GA-253).
Fastener – A nail, screw, or staple used for mechanical application of gypsum panel products (GA-216, GA-253).
Face Layer – The final layer of gypsum panel product applied in a multi-layer application (GA-216).
Fiber – Reinforced Gypsum Panels – A generic name for a family of sheet products consisting essentially of gypsum with fibers dispersed throughout (GA-214).
Finishing – The act of concealing joints with joint compound and tape; concealing fastener heads and edges or flanges of accessories with joint compound (GA-216).
Flat Paint – A paint material specifically manufactured to produce 0 to 5 Gloss Units (GU) at a 60° angle and 0 to 10 Gloss Units (GU) at an 85° angle when measured using a gloss meter (GA-214).
Framing Member – A stud, plate, track, joist, furring, or other support to which a gypsum panel product or metal plaster base is attached (GA-216, GA-253).
Glass Fiber Insulation – An insulaton composed principally of fibers manufactured as a continuous filament from molten glass, with or without binders (GA-600).
Glass Mat Gypsum Panels – A generic name for a family of sheet products consisting of a noncombustible core of essentially gypsum surfaced with glass mat partially or completely embedded in the core (GA-214).
Gypsum Board – A type of gypsum panel product consisting of a noncombustible core primarily of gypsum, with paper surfacing (GA-216, GA-600).
Gypsum Panel Products – Defined in ASTM C11 Standard Terminology Relating to Gypsum and Related Building Materials and Systems, as “the general name for a family of sheet products consisting essentially of gypsum.” Note: This term includes gypsum board, glass mat gypsum panels, fiber-reinforced gypsum panels, and factory-laminated gypsum panels (GA-214, GA-216, GA-600).
Joint Photographing – The shadowing of the finished joint areas through the surface decoration. syn telegraphing (GA-214).
Limited-Load Bearing – A constant superimposed load applied to the test specimen throughout the fire test to simulate a design load less than the maximum allowable design load (GA-600).
Load-Bearing – A constant superimposed load applied to the test specimen throughout the fire test to simulate the maximum allowable design load (GA-600).
Mineral Wool (Insulation) – Defined in ASTM C168 Standard Terminology Relating to Thermal Insulation, as “a synthetic vitreous fiber insulation made by melting predominantly igneous rock, and or furnace slag, and other inorganic materials, and then physically forming the melt into fibers,” (GA-600).
Non-Flat Paint – A paint material specifically manufactured to produce greater than 5 Gloss Units (GU) at a 60° angle and greater than 10 Gloss Units (GU) at an 85° angle when measured using a gloss meter (GA-214).
Non-Load Bearing – No superimposed load applied to the test specimen throughout the fire test GA-600).
Non-Structural Cold-Formed Steel Framing Members – Refers to metal studs and runners complying with AISI S220 – North American Standard for Cold-Formed Steel Framing – Nonstructural Members or ASTM C645 Standard Specification for Nonstructural Steel Framing Members (GA-600).
Parallel Application – The installation of gypsum panel products with edges oriented parallel to framing members (GA-216, GA-253).
Perpendicular Application – The installation of gypsum panel products with edges oriented at right angles to framing members (GA-216, GA-253).
Primer – A material specifically formulated for the intended final finish application to be applied over the entire prepared gypsum panel surface prior to decoration (GA-214).
Regular Gypsum Board – A gypsum board with naturally-occurring fire resistance from the gypsum in the core (GA-600).
Shear Wall – A wall designed and constructed to resist lateral wind or seismic loads (GA-253).
Skim Coat – Either a thin coat of joint compound applied at a trowel consistency, or a material manufactured specifically for this purpose, applied in accordance with manufacturer’s recommendations over the entire surface. For further discussion of trowel consistency and skim coating operation (GA-214).
Spotting – To cover fastener heads with joint compound (GA-214).
Structural Cold-Formed Steel Framing Members – Refers to steel framing members with a base metal thickness from 0.0329 in. (0.836 mm) to 0.118 in. (2.84 mm) complying with AISI S240 – North American Standard for Cold-Formed Steel Structural Members or ASTM C955, Standard Specification for Load-Bearing (Transverse and Axial) Steel Studs, Runners (Tracks), and Bracing or Bridging for Screw Application of Gypsum Panel Products and Metal Plaster Bases (GA-600).
Texture – A decorative treatment applied to gypsum panel surfaces. NOTE: A “non-continuous texture” is a pattern where a portion of the panel surface remains exposed after application (GA-214).
Tool Marks – Imperfections left in joint compound from the use of drywall finishing tools (GA-214).
Treated Joint – A joint between gypsum panel products that is reinforced with tape and joint compound or covered by strip moldings (GA-216).
Type C Gypsum Board – A proprietary type X gypsum board with enhanced fire resistance (GA-600).
Type X Gypsum Board – A gypsum board with special core additives to increase the natural fire resistance of regular gypsum board (GA-600).
Untreated Joint – A joint between gypsum panel products that is left unfinished (GA-216).
Wallcovering – A flexible sheet of sized paper, fabric, plastic, etc., usually laminated and printed with a pattern intended to be pasted to a wall as decoration (GA-214).
Referenced Publications:
• GA-214 Levels of Finish for Gypsum Panel Products
• GA-216 Application and Finishing of Gypsum Panel Products
• GA-253 Application of Gypsum Sheathing
• GA-600 Fire Resistance and Sound Control Design Manual