Attic Air Flow Calculation

Of total vent space needed.

Attic air flow calculation.

A 50 x 30 attic would have a total area of 1 500 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. For projects involving vents with motors the calculation formula is different.

Soffit vents allow outside air to. The solution is to add baffles which allow air to flow past the insulation photo 9. 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. Our passive roof vents are ul certified and rated to withstand wind pressure in excess of 200 mph.

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. How to determine the number of attic vents. Proper air circulation through the attic space helps lower cooling bills and prolongs the life of roofing materials. Enter square footage calculate or enter the square footage of the attic or area to be vented.

Nine hundred square inches equals 6 25 square feet. Ft divided by 150 equals 10 sq. Taking advantage of this natural process referred to as passive ventilation is the most common way to vent an attic. That means air can t flow from the soffit vents to the roof vents.

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. Home attic vent calculator for years we have been working with architects and specifiers to ensure affordable roof ventilation that upholds building code standards. 11 12 roof pitch and higher increase the amount of ventilation by 30 percent. Daily activities in your home such as showering dishwater laundry or having the furnace on generate heat and moisture in the air.

Standard ridge vent produces 18 square inches of ventilating area per lineal foot. Baffles are available at home centers. Proper air ventilation in the roof prevents costly problems like. Hot air exhaust vents located at the peak of the roof allow hot air to escape.

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. Length x width of attic in feet 150 total sq. Attic mold rotting of roof sheathing and framing shortened roof life cracked paint and siding failure or an overheated home. Calculate the total vent area needed.