Attic Ventilation Requirements Ontario

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.

Attic ventilation requirements ontario. Near ridge of the roof. 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. According to the ontario building codes you need one square foot of vent area for each 150 square feet of attic floor space. In order to facilitate this exchange of warm and cool air the general rule of thumb suggests installing at least 1 sq.

The majority of the requirements related to attic ventilation have not changed much from the previous editions. 1 except as provided in sentence 2 the unobstructed vent area shall be not less than 1 300 of the insulated ceiling area. These are changes made in order to increase the energy efficiency of the home and thus also save energy. Building codes vary.

The following are the requirements taken directly from the irc. The change that occurred in the attic insulation in the ontario building code was in the minimum required r value. Based on your 1100 sq. Gaf attic ventilation calculator.

And this guideline you ll need a minimum of. The minimum is one square foot for every 300 square feet of attic floor space if there is a vapor retarder or the space is balanced between the ridge and intake vents. 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. Of vent for every 300 sq.

The recommended r value has been raised from r 50 to r 60 in order to increase the insulation of the attics. Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split. 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. The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.

These types of roofs therefore require more ventilation than common attic type roofs. Vents are rated by their net free area or the amount of space for air to flow in or out.