How Far Apart For Roof Vents

Thus if your attic is 450 square feet you need roof vents equaling 3 square feet.

How far apart for roof vents.

Vegetation must not be allowed to grow within 3 feet of an exhaust vent. Ventsure 4 foot strip heat moisture ridge vent with weather protector moisture barrier. If there is no vapor barrier double it to one square foot of nfa for every 150 square feet of attic floor space half for intake half for exhaust. Provides continuous ridge venting continuous soffit venting and then close off those old gable end vents to force the intake air to come where you want it to flow.

So if your attic is 1 500 sq. This ratio is required for modern insulated homes. If you have 3 000 square feet of attic space this equates to 20 square feet of ventilation needed. Divide the square footage by 150 to calculate the area of ventilation needed since you need 1 square foot of vent space for each 150 square feet of attic space.

This allows air to circulate over the insulation taking away any moisture evaporating upwards or trapped in the insulation fibres. Measure the length and width of the attic and multiply the two together. Choose one of the following products to meet the recommended exhaust nfva of 528 square inches. Exhaust vents must be protected against rain and equipped with back flow prevention features e g flap dampers.

Ventsure 4 foot strip heat moisture ridge vent. The rule of thumb on the amount of vent space needed is approximately 1 sq. 27 lineal feet required. The final number will be the total vent space needed for your attic.

If your attic floor has a vapor barrier you will need one square foot of nfa per every 300 square feet of attic floor area half of that will be intake half for exhaust. Otherwise the exiting air at the ridge will usually pull its makeup air from the closer gable end vents and not from the soffit or eaves vents. In all areas exhaust vents should be at least 1 foot above roof surface. For example 1 500 square feet of attic space requires 10 square feet of vent space.

Take the solution and divide it by 150. 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. These spacing intervals are measured on center meaning that the measurement is taken from the center of one rafter s horizontal surface to the center of the next rafter. Of vent space for every 150 sq.

Optimum roof ventilation design. Ft you divide that by 150 to get 10 sq. What is the standard spacing of a roof rafter. In my opinion one of the best places to fit roof tile vents is normally the bottom third of a roof just above insulation level.