01 May 1999
insulating concrete, formed by heating and
a threaded bolt and an expanding clip that can fit
expanding a micaceous mineral.
through a drilled bolt hole, then spring outward
to provide anchorage from the blind side.
mechanical behavior, from nearly elastic at low
Trim--The light gauge metal used in the finish of
temperature to plastic, like a viscous fluid, at
a building, especially around openings and at
intersections of surfaces. Often referred to as
to flow, measures in centistokes (cSt) for
Tuck pointing--The filling in with fresh mortar of
bitumens. (Water has a viscosity of roughly 1
cutout or defective mortar joints in masonry.
cSt, light cooking oil 100 cSt.)
U-Factor--The heat flow across an entire
Vulcanization--An irreversible process during
assembly e.g., from air within a building to
which a rubber compound, through a change in
outside air; the inverse of R-Factor.
its chemical structure, e.g., cross-linking,
becomes less plastic and more resistant to
Ultimate elongation--The elongation of a
swelling by organic liquids, and elastic proper-
stretched specimen at the time of break. Usually
ties are conferred, improved, or extended over a
reported as percent of the original length. Also
greater range of temperature.
called breaking strain.
Warp--In textiles, the lengthwise yarns in a
Unsupported sheeting--A polymer sheeting one
or more plies thick without a reinforcing fabric
layer or scrim.
vapor flow normal to two parallel surfaces of a
Uplift--Wind load on a building which causes a
material, through a unit area, under the
load in the upward direction. (See Suction)
conditions of a specified test such as ASTM
E96. Customary units are g/hm2 (grains/hft2). 1
Valley gutter--A channel used to carry off water
grain/hft = 0.697 g/hm .
at the intersection of two sloping roof planes.
Waterproofing--Treatment of a surface or
Vapor barrier--See Vapor Retarder.
structure to prevent the passage of water under
Vapor migration--The flow of water vapor from a
region of high vapor pressure to a region of
Weatherometer--An instrument used to subject
lower vapor pressure.
specimens to accelerated weathering conditions,
e.g., rich UV source and water spray.
Vapor pressure--The pressure exerted by a
Wicking--The process of moisture movement by
capillary action as contrasted to movement of
Vapor retarder--A material that resists the flow
Yield strength--(1) The longitudinal stress a
of water vapor.
material can bear before plastic deformation
(i.e., elongation under constant stress); (2) The
Vent--Opening designed to convey water vapor
stress at which a material exhibits a specified
or other gas from inside a building or a building
reduction in the constant stress/strain ratio is the
component to the atmosphere.
Ventilator--An accessory usually used on the
Yield strength--The stress at which a material
roof that allows air to pass through.
exhibits a specified deviation from proportionality
Vermiculite--An aggregate used in lightweight
of stress and strain.