Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.
Open aur needed fir attic exhaust.
Ravc member companies have an extensive offering of intake and exhaust vents.
Attic square footage 4 square inches of exhaust and square inches of intake net free area needed.
Most building codes require a ratio of 1 150 ventilation space to attic floor space.
Ideally there should also be plenty of soffit intake space their calculations recommend 336 net square inches of open soffit ventilation to supply 700 cfm.
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.
Select your preferred type of exhaust system.
Here s an example using the shortcut for the 1 150 code minimum.
Ft of attic space for example 20 x 50 to be effective.
Intake vents located at the lowest part of the roof under.
Cool air in hot air out attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.
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.
Dry air to enter the attic.
You can also contact your local municipality to check on building code in your area.
The uniform building code requires that the amount of venting area in the attic be equal to 1 150 of the area of the floor and in most circumstances it allows a ratio of 1.
2 200 2 1 100 square inches of exhaust net free area needed.
The following product options will allow you to achieve an exhaust nfva of 528 square inches.
In no case should the amount of exhaust ventilation exceed the amount of intake ventilation.
Say the contractor is standing in front of a house that has an attic with 2 200 square feet.