Number Of Roof Vents Required

How to determine the number of attic vents.

Number of roof vents required.

So we would need at least six metal vents in addition to the lower soffit ventilation to meet minimum ventilation requirements. This calculator gives you the required attic ventilation requirement. Thus if your attic is 450 square feet you need roof vents equaling 3 square feet. A normal metal pot vent produces only 50 squares inches of free net area.

Eac 16x4 metal soffit vents. Multiple these two. The next step is to select a suitable exhaust vent and intake vent that fits the roof design for best performance and best aesthetics. 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.

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. And this guideline you ll need a minimum of. 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. Foot of ventilation for every 150 sq.

Next divide that number by 2. Eac 16x8 metal soffit vents. After that find out the vent s nfa as rated by the manufacturer. As a general rule your roof needs 1 square foot of vent area for every 150 square feet of attic space.

The calculations before indicated that we needed 2 square feet of ridge or upper roof ventilation. Two square feet equals 288 square inches. Calculate the square footage of your attic. It s time to install.

Use the calculator below to find out how many exhaust and intake vents you will need on your house. Lsv8 metal continuous soffit vents lineal feet 31 eap 4x12 plastic soffit vents. Based on your 1100 sq. Divide the vent s nfa into 1 100 to yield the number of vents needed either in linear feet or units pieces.

Measure the length and width of the attic space using a tape measure. Feet of attic space divided 50 50 between the inlets and outlets. In our case the required 4 vents for the 1200 sq ft house multiply the 144 cubic inches by 4 576 cubic inches. Embershield closeable soffit vents.

The federal housing administration recommends 1 square foot of attic.