Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.
Attic ventilation requirements canada.
The majority of the requirements related to attic ventilation have not changed much from the previous editions.
Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge.
2 where the roof slope is less than 1 in 6 or in roofs that are constructed with roof joists the unobstructed vent area shall be not less than 1 150 of the insulated ceiling area.
Heat build up the canadian asphalt shingle manufacturers association has issued a bulletin titled proper ventilation for asphalt shingle covered roofs.
Of net free area of exhaust needed at or near the ridge.
Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space.
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Ridge static attic vents 384 00 minimum sq.
Attic ventilation serves a number of purposes.
A ridge vent is a ventilation strip that is placed along the ridgeline of the home.
Vent requirements 1 except as provided in sentence 2 the unobstructed vent area shall be not less than 1 300 of the insulated ceiling area.
For the 1 150 attic ventilation requirement simply double the amount of exhaust and intake calculated.
The ontario building code vent requirements 9 19 1 2.
Prior to installing the ridge vent a 1 inch wide strip of roof decking is cut out along both sides of the ridgeline to allow for air movement through the vent.
Intake vents located at the lowest part of the roof under the eaves.
It is important that air movement occurs and is not impeded by any framing members of the.
After air sealing attic ventilation is your second line of defence against the water vapour that may have found its way into the attic.
It reduces summer heat buildup prolonging the life of roofing and reduces air conditioner loads.
When installed as part of a properly balanced when installed as part of a properly balanced attic ventilation system gaf cobra exhaust vent is a shingle over exhaust vent installed at the roof ridge that helps exhaust excess heat and moisture from your attic.
The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.
The following are the requirements taken directly from the irc.