How Many Roof Vents Do You Need

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.

How many roof vents do you need.

Choosing round soffit vents for this home means that 8 square feet of required ventilation be divided by 0 196 for about 40 round vents. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. This means that you should add more roof vents than 1 per 150 square feet. General rule of thumb is 1 whirlybird for every 50m2 of roof void space.

As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. You ll need the square footage of your attic to calculate the number of roof vents that you should need. Attic ventilation requirements how many attic vents your roof needs industry standard for proper attic ventilation recommends for no vapor retarder type of attic insulation no paper plastic or aluminum layer between the attic floor and insulation layer 1 sq. 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.

Some local building codes carry special considerations that take precedence. For a 3 4 bedroom house 3 roof vents and for a 4 5 bedroom house 4 roof vents. Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation for every 300 square feet of attic floor space evenly split between intake and exhaust. 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.

These specialty vents do not affect the. But if your roof has a slope greater than 6 12 this means that there will be more volume in your attic than the actual square footage. For published install prices in sydney click here average example is for a 2 3 bedroom house you ll need approximately 2 roof vents. Use the calculator below to find out how many exhaust and intake vents you will need on your house.

How many roof vents do i need. Rafter vents or insulation baffles install in any rafter space to create narrow gaps that direct fresh air from the soffit vents to the peak of the roof. Foot of ventilation for every 150 sq. Feet of attic space divided 50 50 between the inlets and outlets.

You should provide an equal distribution between intake and exhaust vents. For example if you have 1200 square feet of attic space you should need at least 4 air vents to ensure proper ventilation. Keep in mind you should always consult with a professional roofing company when determining how many air vents your roof should have.