Number Of Roof Vents Required

Embershield closeable soffit vents.

Number of roof vents required.

Two square feet equals 288 square inches. So we would need at least six metal vents in addition to the lower soffit ventilation to meet minimum ventilation requirements. 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. Use the calculator below to find out how many exhaust and intake vents you will need on your house.

Next divide that number by 2. A normal metal pot vent produces only 50 squares inches of free net area. Calculate the square footage of your attic. Divide the vent s nfa into 1 100 to yield the number of vents needed either in linear feet or units pieces.

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. Now you know how many square inches of attic roof venting you need for the roof and soffit. This calculator gives you the required attic ventilation requirement.

After that find out the vent s nfa as rated by the manufacturer. Near ridge of the roof. 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. Lsv8 metal continuous soffit vents lineal feet 31 eap 4x12 plastic soffit vents.

Multiple these two. In our case the required 4 vents for the 1200 sq ft house multiply the 144 cubic inches by 4 576 cubic inches. It s time to install. Eac 16x8 metal soffit vents.

Foot of ventilation for every 150 sq. Feet of attic space divided 50 50 between the inlets and outlets. Measure the length and width of the attic space using a tape measure. Based on your 1100 sq.

How to determine the number of attic vents. Eac 16x4 metal soffit vents. The next step is to select a suitable exhaust vent and intake vent that fits the roof design for best performance and best aesthetics. And this guideline you ll need a minimum of.

Divide the attic s square footage by 150.