Calculating Minimum Attic Ventilation

Ok to determine how much ventilation area you need for your house all you need to know is the square foot area of the attic to be ventilated.

Calculating minimum attic ventilation.

Divide the square footage item 1 by 300. Attic ventilation is an important part of keeping your building healthy. 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. Calculating attic ventilation requirements.

Length x width of attic in feet 150 total sq. This means that if you have a 1500 sq attic then you would need at least 10 sf of ventilation. Result of item 1 300. Calculating ventilation area of attic kitchen ventilation text.

Calculate the square footage of the attic space. The federal housing authority fha and the urban development hud have established minimum requirements for attic ventilation. Result of item 2 x 144. The following is an example shown in the irc commentary for a simple gable roof using the 1 300 ratio.

A 50 x 30 attic would have a total area of 1 500 sq. A discussion on attic ventilation isn t complete without going over the calculations to determine the minimum required net free ventilating area nfva. 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. According to their requirements you should have 1 square foot of attic ventilation per 300 sq ft of attic floor space.

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. For balanced ventilation an equal amount of intake vent area net free area should also be installed. 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. Change the square feet to square inches.

In order to have a balanced ventilation system you need to have the right roof vent calculation. Multiply the length of the attic times the width in feet to find the attic area then divide by 150 to find the total square feet of vent space needed. Calculate the total vent area needed. Current regulations state that the minimum attic ventilation requirements are 150 1.

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. Ft divided by 150 equals 10 sq. Result of item 3 2. The result of item 4 is the minimum of square inch.

Divide the square inches by 2. The house measures 30 feet by 50 feet. Enter square footage calculate or enter the square footage of the attic or area to be vented.