Number Of Roof Vents Required

Eac 16x4 metal soffit vents.

Number of roof vents required.

Measure the length and width of the attic space using a tape measure. Foot of ventilation for every 150 sq. Embershield closeable soffit vents. Feet of attic space divided 50 50 between the inlets and outlets.

Divide the vent s nfa into 1 100 to yield the number of vents needed either in linear feet or units pieces. A normal metal pot vent produces only 50 squares inches of free net area. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. Lsv8 metal continuous soffit vents lineal feet 31 eap 4x12 plastic soffit vents.

Divide the attic s square footage by 150. 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. Use the calculator below to find out how many exhaust and intake vents you will need on your house. After that find out the vent s nfa as rated by the manufacturer.

Now you know how many square inches of attic roof venting you need for the roof and soffit. In our case the required 4 vents for the 1200 sq ft house multiply the 144 cubic inches by 4 576 cubic inches. Next divide that number by 2. How to determine the number of attic vents.

This calculator gives you the required attic ventilation requirement. 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. As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space. The federal housing administration recommends 1 square foot of attic.

Based on your 1100 sq. Calculate the square footage of your attic. The calculations before indicated that we needed 2 square feet of ridge or upper roof ventilation. Two square feet equals 288 square inches.

The next step is to select a suitable exhaust vent and intake vent that fits the roof design for best performance and best aesthetics. Eac 16x8 metal soffit vents. Multiple these two. It s time to install.

Near ridge of the roof.