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References |
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Glossary
STRIPPING (1) The technique of sealing a joint between metal
and membrane with one or two plies of felt, fabric or membrane
and hot- or cold-applied adhesive; (2) The technique of taping
joints between insulation boards or deck panels.
STYRENE-BUTADIENE-STYRENE RUBBER (SBS) High
molecular weight polymers having rubber-like properties,
formed by the random copolymerization of styrene and
butadiene monomers. Polymers of this type are often
crosslinked to give maximum rubber-like properties in service.
These polymers are sometimes used as the modifying
compound in certain modified bitumen roofing membranes.
SUBSTRATE The surface upon which the roofing or
waterproofing membrane is placed.
SUMP A depression in the surface of a roof around the
opening to a drain, which serves to promote drainage.
SUPER-STEEP ASPHALT A roofing asphalt conforming to
requirements of ASTM Specification D 312, Type IV. Also
known as SPECIAL STEEP ASPHALT.
TAPERED EDGE STRIP A tapered insulation strip used to
elevate the roofing at the perimeter and at penetrations of the
roof.
TAR See COAL TAR PITCH.
TAR BOILS Bubbles of moisture vapor encased in a thin film
of asphalt. Also blueberry, strawberry or raspberry.
TEAR OFF To remove an existing roofing system down to the
structural deck.
TEAR RESISTANCE The load required to tear a material
when the stress is concentrated on a small area of the
specimen by the introduction of a prescribed flaw. Expressed
in pounds force (N) or pounds per lineal inch.
TENSILE STRENGTH The maximum force or stress required
to break a membrane sample during a tensile test.
THERMAL INSULATION A material applied to retard the flow
of heat.
THERMAL SHOCK The stress-producing phenomenon
resulting from sudden temperature drops in a roof membrane
when, for example, a rain shower follows brilliant sunshine.
THERMOPLASTIC Polymers which soften when heated and
harden when cooled. This process is reversible provided the
material is not heated above the point at which decomposition
occurs.
THERMOSET A material that solidifies or "sets" irreversibly
when heated. This property is usually associated with
crosslinking of the molecules induced by heat or radiation.
THROUGH-WALL FLASHING A water-resistant membrane
or material assembly extending totally through a wall and its
cavities, positioned to direct any water within the wall to the
exterior.
ULTIMATE ELONGATION The amount a material stretches
during tensile testing before it ruptures, usually expressed as a
percentage of the original length.
UMBRELLA See BONNET.
UNDERWRITERS LABORATORIES (UL) An independent,
non-profit agency which functions as the testing arm of the
National Board of Fire Underwriters. It maintains laboratories
for the examination and testing of various devices, systems,
and materials to determine their safety against the hazards of
fire and accident. UL is organized around a number of
separate departments, including "Chemical Hazards,"
"Electrical Hazards," and "Fire Protection."
VAPOR RETARDER Sheet material installed to impede or
restrict the passage of water vapor through a roofing assembly.
VENT An opening designed to convey water vapor or other
gas from inside a building or a building component to the
atmosphere. (Also ROOF VENT.)
VERMICULITE An aggregate used in lightweight insulating
concrete, formed by heating and expanding a micaceous
mineral.
VOID An absence of adhesive between two layers of
membrane.
WALK IN To embed insulation panels in hot asphalt or
adhesive by walking on them immediately after application.
WATER CUTOFF MASTIC A thermoset material used to form
a seal between single ply membrane sheets at indicated
termination points.
WATER VAPOR TRANSMISSION A measure of the rate of
transmission of water vapor through the membrane material
under controlled laboratory conditions of temperature and
humidity.
WIND SCOURING Erosion of ballast or surfacing due to wind.
