How Many Roof Vents Should You Have

Enter square footage calculate or enter the square footage of the attic or area to be vented.

How many roof vents should you have.

The building code lets you reduce that by half under some conditions but more roof ventilation is usually better. You ll need the square footage of your attic to calculate the number of roof vents that you should need. For example if you have 1200 square feet of attic space you should need at least 4 air vents to ensure proper ventilation. Hot air exhaust vents located at the peak of the roof allow hot air to escape.

As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. Attic for example has an area of 1 200 sq. Taking advantage of this natural process referred to as passive ventilation is the most common way to vent an attic. A 30 x 40 ft.

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. 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. Solid vinyl soffit material costs the same as the vented material. First determine your attic area by multiplying the length by the width.

Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. Foot of ventilation for every 150 sq. In of vent opening per 150 sq. If the home already has a fan roof vents or gable vents these should be blocked and sealed from the attic side of the home.

8 perform similar calculations for the roof and ridge vents. Feet of attic space divided 50 50. If you have a hip roof with very little ridge a power fan with both a thermostat and humidistat for both temperature and humidity should be installed with no ridge vent. 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.

It s important to remember that it s better to have too much intake ventilation than too little and many homes often undercalculate the amount of intake needed so worry less about having too much intake and err on the side of having more. Attic ventilation requirements how many attic vents your roof needs. They should be divided equally between inlet and outlet vents and they can be used in any combination that will work with your roof s design.