Attic Air Flow Calculation

The solution is to add baffles which allow air to flow past the insulation photo 9.

Attic air flow calculation.

Proper air circulation through the attic space helps lower cooling bills and prolongs the life of roofing materials. Proper air ventilation in the roof prevents costly problems like. Daily activities in your home such as showering dishwater laundry or having the furnace on generate heat and moisture in the air. Calculate the total vent area needed.

Baffles are available at home centers. 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. Taking advantage of this natural process referred to as passive ventilation is the most common way to vent an attic. Of total vent space needed.

11 12 roof pitch and higher increase the amount of ventilation by 30 percent. Standard ridge vent produces 18 square inches of ventilating area per lineal foot. Attic mold rotting of roof sheathing and framing shortened roof life cracked paint and siding failure or an overheated home. Home attic vent calculator for years we have been working with architects and specifiers to ensure affordable roof ventilation that upholds building code standards.

How to determine the number of attic vents. Nine hundred square inches equals 6 25 square feet. For projects involving vents with motors the calculation formula is different. Ft divided by 150 equals 10 sq.

7 12 to 10 12 roof pitches increase the amount of ventilation by 20 percent. If your attic is well insulated the insulation might be plugging the spaces between rafters just above exterior walls. That means air can t flow from the soffit vents to the roof vents. 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.

A 50 x 30 attic would have a total area of 1 500 sq. Hot air exhaust vents located at the peak of the roof allow hot air to escape. Length x width of attic in feet 150 total sq. 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.

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. Our passive roof vents are ul certified and rated to withstand wind pressure in excess of 200 mph. Enter square footage calculate or enter the square footage of the attic or area to be vented. Up to 6 12 roof pitch use the standard formula as explained in this article.