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 joint that accommodates movement of gypsum panel products resulting from positional or dimensional change, as based upon the definition in ASTM E631 Standard Terminology of Building Constructions (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 between two building elements that allows free movement between the elements, as based upon the definition in ASTM D1079 Standard Terminology Relating to Roofing and Waterproofing (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 and 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 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 – Defined in ASTM C11 Standard Terminology Relating to Gypsum and Related Building Materials and Systems, as “the generic name for a family of sheet products 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).
Metal Studs – Refers to steel studs and runners (track) not less than 0.0179 inch base metal thickness and manufactured to comply with ASTM C645 Standard Specification for Nonstructural Steel Framing Members, unless otherwise specified in the detailed description (GA-600).
Mineral Fiber – Defined in ASTM C168 Standard Terminology Relating to Thermal Insulation, as “insulation composed principally of fibers manufactured from rock, slag, or glass, with or without binders,” (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).
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).
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 exposed. Additional definitions are contained in ASTM C11 Standard Terminology Relating to Gypsum and Related Building Materials and Systems (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