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.

What is the standard spacing of a roof rafter. 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. If you have 3 000 square feet of attic space this equates to 20 square feet of ventilation needed. Of vent space for every 150 sq.

Ventsure 4 foot strip heat moisture ridge vent with weather protector moisture barrier. 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. 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. 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. But they do tend to space rafters in one of several industry standard increments typically either 12 16 or 24 inches apart. So if your attic is 1 500 sq. This ratio is required for modern insulated homes.

This allows air to circulate over the insulation taking away any moisture evaporating upwards or trapped in the insulation fibres. 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. The final number will be the total vent space needed for your attic. Optimum roof ventilation design.

Exhaust vents must not be allowed to be obscured or hidden by vegetation. 27 lineal feet required. Exhaust vents must be protected against rain and equipped with back flow prevention features e g flap dampers. Take the solution and divide it by 150.

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. Measure the length and width of the attic and multiply the two together. In all areas exhaust vents should be at least 1 foot above roof surface. Ventsure 4 foot strip heat moisture ridge vent.

The rule of thumb on the amount of vent space needed is approximately 1 sq. Choose one of the following products to meet the recommended exhaust nfva of 528 square inches. For example 1 500 square feet of attic space requires 10 square feet of vent space. 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.