Ratio Of Soffit Vents To Roof Vents

Roof vents choose one of the following products to meet the recommended exhaust nfva of 528 square inches.

Ratio of soffit vents to roof vents.

Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space. Ventsure 4 foot strip heat moisture ridge vent. Rafter vents or insulation baffles install in any rafter space to create narrow gaps that direct fresh air from the soffit vents to the peak of the roof. Resin circular mini wall louver soffit vent in white 6 pack model rlsc2 view the master flow intake vents 9 28 9 28.

An important part of installing any system of ventilation into your roof system is to make sure that there is a point of entry and a point of exit for airflow. Determine the amount of intake venting required. Master flow 15 amerimax home products 1 deflect o 1 gibraltar building products 1 mounting position. One square foot equals 144 square inches so the standard 16 inch by 8 inch soffit vent is 0 89 square feet.

These specialty vents do not affect the. For example if you use 16 inch by 8 inch soffit vents each vent is 128 square inches. To balance this you need 2 soffit eave intake vents of approximately 10 sq. For roofs with a 7 12 to 10 12 roof pitch you may want to add 20 percent more cfm.

In net free vent area nfva in the soffit intake than at the ridge. As a homeowner it is important that you review the soffit areas of the home for soffit vents. In nfva per lineal foot. Choosing round soffit vents for.

And for roofs 11 12 pitch and higher add 30 more cfm to handle the larger volume of attic space. But the ratio of intake air to outlet air is of critical importance too. Divide this by 144 to calculate how many square feet each vent is. An equal or greater amount of vent opening sq.

Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge. Where eave or cornice vents note. Master flow 2 in. P er lineal foot 1 2of 20 in each overhang.

For the number of soffit vents in the example divide 8 square feet of ventilation needed by 0 5 for the number of rectangular vents required 16 in the example. For example our v 600 products have 20 sq.