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References |
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Glossary
CRICKET A relatively small, elevated area of a roof
constructed to divert water from a horizontal intersection of the
roof with a chimney, wall, expansion joint, or other projection.
CURB A masonry, metal or wood edge extending above the
roof deck at openings for roof-mounted equipment.
CUT BACK Solvent-thinned asphalt used in cold-process
roofing adhesives, flashing cements and roof coatings.
CUTOFF A detail designed to prevent lateral water movement
into the roofing system where the membrane terminates at the
end of a day’s work, or used to isolate sections of the roofing
system.
DEAD LEVEL Absolutely horizontal, or zero slope.
DEAD LEVEL ASPHALT A roofing asphalt conforming to the
requirements of ASTM Specification D 312, Type I.
DECK The structural surface to which the roofing or
water-proofing system (including insulation) is applied.
DEW POINT The temperature at which an air mixture is
saturated with water vapor. If the temperature is at or below the
dew point, condensation will occur.
DIMENSIONAL STABILITY The change in length and/or width
of a material that results from exposure to the elements over
time.
DIPPER A device used to dip and pour hot asphalt.
DOUBLE POUR To apply two layers of aggregate and asphalt
to a bituminous roof.
DRY FELT A felt which has not been saturated with asphalt.
EDGE STRIPPING Application of felt strips cut to narrower
widths than the normal felt-roll width to cover a joint between
flashing and built-up roofing.
EDGE VENTING The practice of providing regularly spaced
protected openings at a roof perimeter to relieve water vapor
pressure in the roofing system.
ELASTOMERIC MEMBRANES A broad group of sheet
materials which possess elastomeric or elastic rubber-like
properties. Elastomeric materials and membranes may be
manufactured from a variety of polymers.
ELONGATION The ability of a roofing membrane material to
be stretched or elongated by the application of a force.
EMBEDMENT The process of pressing a felt, aggregate,
fabric, mat, or panel uniformly and completely into hot asphalt
or adhesive to ensure intimate contact at all points. (Also
BROOMING.)
EMBRITTLEMENT The loss of flexibility, elasticity, or ductility
of a material. The transition of a flexible material to a brittle
material.
EMULSION An intimate mixture of asphalt and water, with
uniform dispersion of the asphalt or water globules, usually
stabilized by an emulsifying agent or system.
ENVELOPE A continuous membrane edge seal formed at the
perimeter and at penetrations by folding the base sheet or ply
over the plies above and securing it to the top of the
membrane. The envelope prevents asphalt seepage from the
edge of the membrane.
EQUILIBRIUM MOISTURE CONTENT (1) The moisture
content of a material stabilized at a given temperature and
relative humidity, expressed as a percent moisture by weight;
(2) The typical moisture content of a material in any given
geographical area.
EQUIVISCOUS TEMPERATURE (EVT) The temperature at
which the viscosity of an asphalt is 125 cST (125 mm2/s) [75
cST(75mm2/s) for machine applications]; the recommended
asphalt temperature ±25°F (±14°C) at the time of application to
the substrate.
ETHYLENE PROPYLENE DIENE TERPOLYMER (EPDM)
An elastomeric material synthesized from ethylene, propylene,
and small amounts of diene monomer. EPDM is widely used in
single ply roofing membranes.
EXPANDED POLYSTYRENE (EPS) A roof insulation board
formed from expanded beads of a plastic polymer molded into
blocks and then cut to size.
EXPANSION JOINT A structural separation between two
building elements that allows free movement between the
elements without damage to the building or roofing system.
EXPANSION JOINT COVER A building element which
waterproofs and seals an expansion joint in a structure.
Typically made from elastomeric materials and/or metal.
EXPOSURE (1) The transverse dimension of a roofing
element not overlapped by an adjacent element in any roofing
system; (2) The time during which a portion of a roofing
element is exposed to the weather.
EXTRUDED POLYSTYRENE A roof insulation board formed
from a polystyrene polymer with integral closed cells, by a
continuous extrusion process.
FACTORY MUTUAL (FM) A group of insurance companies
which insures large industrial and commercial properties in the
U.S. and Canada. Factory Mutual Research Corporation tests
and classifies roof assemblies and components based on their
fire characteristics, and resistance to wind uplift and hail
damage.
