How Many Vents Does My Roof Need

For the 1 150 attic ventilation requirement simply double the amount of exhaust and intake calculated.

How many vents does my roof need.

The general rule of thumb in these situations is of roughly one vent per every 300 square feet of attic area if the attic has a vapor barrier. How many vents will my house need. This means that for every 300 square feet of enclosed attic space 1 square foot of ventilation is required with half at the upper portion exhaust. A single 14 inch diameter turbine vent that is subjected to 15 mph winds can expel up to 1 342 cfm of air.

Soffit vents are vital in keeping air flowing throughout your attic space. Most codes use the 1 300 rule for minimum residential attic ventilation recommendations. If the winds are still the vents still allow air to drift up and out of the attic space although not nearly as much. Of net free area of intake needed at or near the soffit.

As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. 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. The first step in determining how many vents you need is to calculate the net free area nfa required. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet.

The majority of roofing experts agree that ridge vents are the most effective and cost effective roof vents available. Ventsure 4 foot strip heat moisture ridge vent. Of net free area of exhaust needed at or near the ridge. These specialty vents do not affect the.

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. How many vents do i need. I have roof vents so i have roof ventilation. 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.

Take for example ridge vents. Choose one of the following products to meet the recommended exhaust nfva of 528 square inches. There are a number of different types of vents to choose from so getting the ones to suit you should not be difficult although you will still need to work out how many to purchase. While hardly anybody agrees on the best roof ventilation system everybody agrees some roof vents do hardly any good at all.

Even if you have vents in your roof you still need to have soffit vents to allow the air to circulate naturally. 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. Other types there are also several other types of roof vents including dome or box shaped vents that run through the roof itself. Watch my video below.