Standard ridge vent produces 18 square inches of ventilating area per lineal foot.
Attic air flow calculation.
Up to 6 12 roof pitch use the standard formula as explained in this article.
11 12 roof pitch and higher increase the amount of ventilation by 30 percent.
Ft divided by 150 equals 10 sq.
Hot air exhaust vents located at the peak of the roof allow hot air to escape.
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.
Length x width of attic in feet 150 total sq.
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.
Enter square footage calculate or enter the square footage of the attic or area to be vented.
Daily activities in your home such as showering dishwater laundry or having the furnace on generate heat and moisture in the air.
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.
7 12 to 10 12 roof pitches increase the amount of ventilation by 20 percent.
Soffit vents allow outside air to.
Proper air circulation through the attic space helps lower cooling bills and prolongs the life of roofing materials.
Attic mold rotting of roof sheathing and framing shortened roof life cracked paint and siding failure or an overheated home.
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.
Nine hundred square inches equals 6 25 square feet.
Of total vent space needed.
The solution is to add baffles which allow air to flow past the insulation photo 9.
Let s see how a standard ridge vent product will calculate out.
That means air can t flow from the soffit vents to the roof vents.
Baffles are available at home centers.
Proper air ventilation in the roof prevents costly problems like.
Our passive roof vents are ul certified and rated to withstand wind pressure in excess of 200 mph.
How to determine the number of attic vents.
For projects involving vents with motors the calculation formula is different.
Home attic vent calculator for years we have been working with architects and specifiers to ensure affordable roof ventilation that upholds building code standards.
Calculate the total vent area needed.
A 50 x 30 attic would have a total area of 1 500 sq.
