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Brick Vent for
CMU
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 | Description: The
Williams-Goodco brick vent is an injection molded vent made from
flexible polyvinyl chloride in an offset "T" shape. When inserted in
vertical mortar joints between two bricks the slotted leg of the vent
allows air to pass in and out allows water to weep out and prevents
water from penetrating in.
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| Spacing of Brick Vents:
Tests indicate that for interior/exterior air pressure equalization and
for ventilation one Williams-Goodco Brick Vent to every 10 square feet
of wall surface is acceptable. One per 100 square feet is a minimal
number. For drainage of condensation and moisture the vents act as
weepholes and should be placed directly on top of the thru-wall
flashing. One vent for every 24 inches of horizontal flashing is
acceptable to provide weephole drainage.
The vents are hardly noticeable after installation but a regular
symmetrical spacing pattern gives the best appearance.
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| Functions: When
rain contacts an exterior brick surface water can enter openings
through any combination of the following actions: momentum of raindrops,
capillary action, gravity and air currents. Cracks, joints between wall
components, surface pores and inadequately bonded interfaces may provide
the openings for water penetration through walls. Much of the water
penetration through brick cavity walls is caused not by the driving wind
and rain on the exterior face but by the suction created within the air
cavity by the lower interior air pressure. This force is controlled by
installing brick vents in sufficient frequency and size to allow almost
immediate air pressure equalization. Since winds gust, rather than
create steady pressure, vents must have enough opening area to allow a
continuous exchange of air. Small tubes and wicks have generally
proved inadequate because of their limited opening size and
because they clog quickly.
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| Efflorescence:
Efflorescence is reduced by minimizing rain wetting within the exterior wall.
However, more absorptive brick will hold moisture from exterior rain, or
condensation on the back face resulting from air leakage from the building
interior, and under certain environmental conditions (particularly in late
Fall) this presence of moisture can trigger efflorescence.
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| Glazed Brick, Paints or
Silicones: When these materials are used, cavity walls are necessary
to avoid serious problems. In most buildings, moisture laden air will leak
from the building interior and unless some free passage is available to the
outside, spelling, ice lensing or blistering can occur.
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| Test Reports: Tests
have been conducted to determine the rates of air flow through the
Williams-Goodco brick vent and to indicate acceptable spacing for exterior
walls. The test procedures and results are published and available on request.
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| Material Specifications:
The Williams-Goodco brick vent is manufactured from a polyvinyl chloride
compound specifically designed for continuous exposure to weathering. This
compound possesses excellent sunlight resistance, good low temperature
properties and contains a polymeric plasticizer to ensure permanence. Physical
Properties as determined on molded specimens by ASTM procedures:
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| Packaging: 200 vents
per carton.
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| Color: Light gray.
Special Colors Available.
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| Sizes:
2-1/2", 2-3/4", 3-5/8"
will fabricate special sizes
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| Short Form Specification:
Williams-Goodco brick vents as supplied by Williams Products, Inc. shall be
installed in the vertical mortar joints in the exterior masonry brick wall...
(a) As detailed on the drawings. (b) Directly above all through-wall
flashings at (spacing). (c) Throughout the wall in every (i.e. 4th mortar
joint) horizontally and every (i.e. 10th course) vertically.
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| Features:
(1) Top-flap - overlaps two adjacent bricks to stop mortar from falling into
the air passage.
(2) Flexible Wings - to adjust to variation in mortar joint widths (5/16" -
3/4").
(3) Louvers - to allow air passages while creating a water barrier.
(4) Water ridges - when water buildup on the exterior wall surface is blown
into the air passage these ridges create a barrier which directs the rain down
and out of the cavity
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| Provide adequate opening for immediate air
pressure equalization.
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| Act as weeper.
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| Provide neat, attractive appearance.
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| Install easily.
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| Impede passage of insects, din and rodents.
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| Block entrance to rain.
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| Resist clogging and the corrosive effects of
masonry mortars.
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