Required Residential Roof Vents

Next divide that number by 2.

Required residential roof vents.

The minimum net free ventilation area shall be 1 300 of the vented space provided one or more of the following conditions are met. Effective attic ventilation systems reduce damaging heat and moisture in your attic promote energy efficiency by helping to reduce the load on your air conditioner in the summer and also reduce the risk of ice dam formation on your roof. For projects involving vents with motors the calculation formula is different. Up to 6 12 roof pitch use the standard formula as explained in this article.

A new roof is more than just shingles. 11 12 roof pitch and higher increase the amount of ventilation by 30 percent. Solar and other residential products solar and other residential products. Although there are many different types of roof vents to choose from ensuring you have the right number of both.

Of net free area of intake needed at or near the soffit. Ventsure 4 foot strip heat moisture ridge vent. In climate zones 14 and 16 a class i or ii vapor retarder is installed on the warm in winter side of the ceiling. Roof vents choose one of the following products to meet the recommended exhaust nfva of 528 square inches.

Ridge static attic vents 384 00 minimum sq. Solar and other residential products. Now you know how many square inches of attic roof venting you need for the roof and soffit. The minimum net free ventilating area shall be 1 150 of the area of the vented space.

Although soffit vents are not specifically mentioned as required both the international residential code irc and residential edition of the florida building code fbc r806 2 require an attic ventilation area of at least 1 150 of the area being ventilated which works out to be about one inch of ventilation opening for every square foot of attic area and not less than 40 percent and. Master flow power attic vents roof mount. Not less than 40 percent and not more than 50. The building codes and building science for.

Of net free area of exhaust needed at or near the ridge. The installation of roof vents is a crucial part of roof design because it allows for proper attic ventilation which may help prevent condensation and early aging of your roofing materials. Advantages of proper roofing ventilation. Vent roofs with steeples towers or cupolas can be found in different buildings from barns to cathedrals.

In our case the required 4 vents for the 1200 sq ft house multiply the 144 cubic inches by 4 576 cubic inches. The idea of roof vents existed for hundreds of years with natural vents employed in chinese buildings during the tang dynasty natural ventilation ducts in the buddhist monks caves and wind catchers incorporated in arabian architecture. This calculator gives you the required attic ventilation requirement.