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Cor-A-Vent
Purlin Vent
 Is
your insulation a wet blanket? Chances are it is. You
know the problems all too well—cold side condensation
on your metal roof and siding. You probably can’t
see it, but, it could be robbing you blind.
Even
slight amounts of moisture in blanket insulation can
seriously reduce its R-value. Don’t count on
vapor barriers—every seam and penetration has
to be sealed perfectly, and how often does that happen
on the job? Moisture vapor penetrates just about everything,
and once it’s trapped, you have problems. The
heating bill goes up, insulation can sag and the roof
fasteners and purlins will start to rust. What do you
do? Next building, you specify Purlin Vent™,
from Cor-A-Vent—“The Leader In Innovative
Rooftop Ventilation” ®
Purlin
Vent is the first real system solution for venting
behind roofing and siding in metal buildings. Made
from sheets of crush proof profile extruded PP* Purlin
Vent serves as an excellent thermal break between the
metal roof and the purlin when foam insulation is used.
For blanket insulation, Purlin Vent with Insulation
Shield does two things. One, it keeps the blanket insulation
away from the underside of the roof. Two, it creates
a passageway for moisture to diffuse harmlessly to
the outside. When used with any of Cor-A-Vent’s
metal roof ridge vent applications, it creates a very
effective system for removing moisture and keeping
your insulation dry.
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Performance
Purlin Vent can carry a load as well.
One square foot of the 6-ply PP boards COR-A-VENT
uses, equal to a 4-foot piece of Purlin Vent, passed
crush tests, conducted by an independent agency,
up to 7,653 lbs.
Call COR-A-VENT at (800) 837-8368 for more information on new Purlin Vent, including
the Purlin Vent Calculator, COR-A-VENT’s formula to figure out just how
much ventilation your metal building will need to stay dry for years to come. |
Key Benefits
• Provides cross ventilation both horizontally and vertically between the
purlins.
• Provides a thermal break with an R value of 3.1.
• Net free vent area (NFVA) of 40 sq. in. per 4' section
• Made from thermally stable, crush resistant polypropylene (PP) sheets.
• Doesn't compress over time, so roofing & siding screw holes don't
elongate and leak.
• Supplements ASHRAE 90.1 - 1999 Model Energy Code (MEC) requirements when
vapor barriers greater than 1 perm are used.
• NAIMA, NIA and 2000IEEC call for cold side ventilation as a design consideration
in controlling condensation and meeting required U values of the Model Energy
Code. |
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