Formula For Proper Attic Ventilation

Here are the answers to the five most frequent questions pertaining to calculating attic ventilation.

Formula for proper attic ventilation.

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. Proper air ventilation in the roof prevents costly problems like. Calculation q a. Daily activities in your home such as showering dishwater laundry or having the furnace on generate heat and moisture in the air.

The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction. Calculate or enter the square footage of the attic or area to be vented. The house measures 30 feet by 50 feet. Of vent area with half under the eaves in the soffit and half near the peak as either gable or ridge vents.

But the shortcut is just as good and faster. Soffit vents alone are not enough to provide proper attic ventilation. 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. Ventilation can be accomplished using various products and techniques.

Divide the attic s square footage by 150. The following are the requirements taken directly from the irc. Calculating ventilation area of attic kitchen ventilation text. Attic mold rotting of roof sheathing and framing shortened roof life cracked paint and siding failure or an overheated home.

For a 30 x26 attic 780 sq. Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed. Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator. The federal housing administration recommends 1 square foot of attic ventilation for every 150 square feet of attic space.

Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. Cool air in hot air out. Ft you would need at least 5 2 sq. Ensuring your home has the proper attic ventilation according to these guidelines however can save yourself the stress and hassle of an emergency roof repair.

Let s use the following simple ranch house for an example.