Glaze coat. A thin, protective coating of bitumen applied to the
lower surface or to the top ply of a built-up roof when
application of flood coat and aggregate is delayed. It sometimes
refers to an asphalt coating on a smooth-surfaced, built-up
Grain. Weight unit equal to 1/7,000 lb, used in measuring
atmospheric moisture content.
See Mineral Granules.
Gravel. Coarse, granular aggregate resulting from natural
erosion or crushing of rock, used as protective surfacing or
ballast on roof systems.
Gravel stop. Flanged device, usually metallic, with vertical
projection above the roof level and fascia, designed to prevent
loose aggregate from rolling or washing off the roof and to
provide a finished edge detail for the roof.
Gravelling in. Process of embedding aggregate surfacing into a
bituminous membrane flood coat.
Grout. A fluid mixture of cement and water, or a mixture of
cement, sand and water.
Head lap. Minimum distance, measured perpendicular to eave along
the face of a felt or shingle from its upper edge to the nearest
Holiday. Area where interply bitumen mopping or other fluid-
applied coating is discontinuous.
Sheet-metal cover over piping or other rooftop equipment.
"Hot stuff" or "hot".
Roofer's term for hot bitumen.
Absorptive of moisture; readily absorbs and retains
Ice dam. Drainage-obstructive ice formation at eave of snow-
covered sloped roof, caused by refreezing of water melted by
escape of interior heat.
Inorganic. Comprising matter not of plant or animal origin.