01 May 1999
Grain--Weight unit equal to 1/7000 Ib, used in
Framed opening--Frame work (headers and
measuring atmospheric water vapor content.
jambs) and flashing which surround an opening
in the wall or roof of a building; usually for field-
Granule--See Mineral Granules.
installed accessories such as overhead doors or
powered roof exhausters.
Gravel--Coarse, granular aggregate, with
pieces larger than sand grains, resulting from
"Free carbon" in tars--The hydrocarbon fraction
the natural erosion of rock.
precipitated from a tar by dilution with carbon
Gravel stop--Flanged device, usually metallic,
Friability--The tendency of a material or product
designed to prevent loose aggregate from
to crumble or break into small pieces easily.
washing off the roof and to provide a continuous
finished edge for the roofing.
Gable roof--A ridged roof that terminates in
Green building technology--Utilizing technology
to reduce impact on the earth.
Galvalume--Trade name for steel coated with
recyclability, reduction in carbon dioxide, ozone
aluminum-zinc alloy for corrosion protection.
or other atmospheric pollutants, and reduction of
urban heat islands.
Galvanic cell--A cell in which chemical change
is the source of electrical energy. It usually
Grout--Mixture of cement, sand, and water used
consists of two dissimilar conductors in contact
to fill cracks and cavities. Often used under base
with each other and an electrolyte.
plates or leveling plates to obtain uniform
Galvanized steel--Steel coated with zinc for
Gutter--A channel member installed at the eave
of the roof for the purpose of carrying water from
Glass felt--Glass fibers bonded into a sheet with
the roof to the drains or down spouts.
resin and suitable for impregnation in the
manufacture of bituminous waterproofing,
Haunch--The deepened portion of a column or
roofing membranes, and shingles.
rafter, designed to accommodate the higher
bending moments at such points. (Usually
Glass mat--A thin mat of glass fibers with or
occurs at connection of column and rafter.)
without a binder.
Header--A horizontal framing structural member
Glass transition--The reversible change in an
of a door, window, or other framed opening.
amorphous polymer or in amorphous regions of
a partially crystalline polymer from (or to) a
Headlap--The minimum distances measured at
viscous or rubbery condition to (or from) a hard
90 degrees to the eave along the face of a
and relatively brittle one.
shingle or felt as applied to a roof, from the
Glaze coat--(1) The top layer of asphalt in a
upper edge of the shingle or felt, to the nearest
smooth surfaced built-up roof assembly; (2) A
thin protective coating of bitumen applied to the
lower plies or top ply of a built-up membrane,
Heat capacity--The amount of energy required
when application of additional felts, or the flood
to raise the temperature of a unit substance 10F
coat and aggregate surfacing are delayed.
Gloss--Subjective term describing the relative
Heat seaming--The process of joining two or
more thermoplastic films or sheets by heating
areas in contact with each other to the
temperature at which fusion occurs. The process
is usually aided by a controlled pressure. In