Proper attic ventilation can be an impor tant performance consideration when design ing and installing steep slope roof systems.
Calculating attic ventalation.
But the shortcut is just as good and faster.
This calculates the 2015 international residential building code minimum irc section r806 roof ventilation 1 which states that 1 square foot of net free area for every 150 square feet of attic floor space with the attic.
Typically building codes include minimum requirements applicable to attic ventilation.
Hence you would need two square feet 600 300 of attic ventilation.
The roofing industry also has practical guide lines for attic ventilation.
Roof mount power fans are a type of motor driven attic exhaust vent that make up half of a balanced attic ventilation system for each roof.
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.
According to the fha federal housing administration us for every 300 square feet of attic floor area you should have at minimum one square foot ventilation.
Most attic ventilation manufacturers list the longer formula on their websites and inside key product brochures.
Code requirements the international building code.
Width or area.
So if your attic is 1 500 sq.
To calculate nfa take the attic square footage 2 square inches of exhaust and square inches of intake nfa needed.
Roof ventilation calculator enter your attic area or length and width to determine your ventilation needs.
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.
To use this calculator first find the total square footage of the attic floor area.
Of vent space for every 150 sq.
Here are the answers to the five most frequent questions pertaining to calculating attic ventilation.
Then look across to the number under the minimum length of ridge column.
Enter square footage calculate or enter the square footage of the attic or area to be vented.
Ridge vent intake vent calculator for standard gable attic.
As an example in an attic that is 30 feet by 20 feet you would have 600 square feet of floor area.
Ft you divide that by 150 to get 10 sq.
The rule of thumb on the amount of vent space needed is approximately 1 sq.
Round your calculations up to the next highest number see ventilations requirements.
Calculation q a.
