Air vent recommends 1 square foot of ventilation for every 150 square feet of attic floor space with half the ventilation represented by intake vents and half by exhaust vents such as ridge vents.
Attic ventilation requirements ontario.
For the 1 150 attic ventilation requirement simply double the amount of exhaust and intake calculated.
As ventilation rates vary with wind speed and direction the magnitude of natural ventilation is difficult to predict.
Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems.
Of net free area of intake needed at or near the soffit.
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.
You can calculate attic ventilation requirements by determining the square footage of your attic.
The ontario building code vent requirements 9 19 1 2.
For minimum building code requirements use the 1 300 ratio instead of the 1 150 ratio.
Of net free area of exhaust needed at or near the ridge.
Ridge static attic vents 384 00 minimum sq.
Bathrooms can only benefit from some type of exhaust venting system but which type do you need and what does the bathroom exhaust fan venting.
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.
Typically building codes include minimum requirements applicable to attic ventilation.
However in canada the largest contributor to infiltration is the temperature difference between the inside of the house and the outside causing in a phenomenon called stack effect.
The key to proper ventilation of your roof and attic is balance.
Intake vents located at the lowest part of the roof under the eaves allow cool.
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.
Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator.
Moisture though is the real problem since it can create potentially hazardous mold and mildew eating away at your walls ceiling and trim.
The amount of space you devote to intake must be equal to the amount you allow for exhaust and these must be calculated according to the size of your attic and slope of your roof.
Code requirements the international building code.
Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.
Bathrooms are wet smelly places that often are closed in and unventilated.
