Eave Input Vent Area To Floor Square Ft Ratio

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.

Eave input vent area to floor square ft ratio.

This is distributed between under eave net free vent area and the ridge in a ratio of 60 under eave and 40 in the ridge. This ratio is required for modern insulated homes. 150 6 6 square feet of total net free area 3. And this guideline you ll need a minimum of.

30 lineal feet required. For round vents multiply the radius of the vent half the diameter times itself squared then multiply the total by 3 14 pi and divide by 144 to find the number of square feet r in inches x 3 14 144 sq. In no case should the amount of exhaust ventilation exceed the amount of intake ventilation. Determine the total net free area required.

30 feet x 50 feet 1 500 square feet. Ok so now we know the square footage of the attic area to be ventilated. 1 square foot of nfva per 300 square feet of attic floor if a vapor barrier is installed on the ceiling below. For example a single story house with 2000 square foot of roof floor area would require 13 3 square feet or 1920 square inches of vent area.

If you have 3 000 square feet of attic space this equates to 20 square feet of ventilation needed. Divide the square footage by 150 to calculate the area of ventilation needed since you need 1 square foot of vent space for each 150 square feet of attic space. Based on your 1100 sq. A 6 x 12 vent would equal 72 sq.

1 100 square inches of intake net free area needed. Once attic square footage is known divide by 150 for the 1 150 ratio. 1 500 square feet. Remember the minimum area requirement when using a continuous system is a ratio of 1 300.

40 x 25 1 000 square feet of attic area 2. In divided by 144 equals an area of 0 5 sq. Always have a balanced ventilation system. Say the contractor is standing in front of a house that has an attic with 2 200 square feet.

2 200 2 1 100 square inches of exhaust net free area needed. So in our example we will divide the 1 500 square feet by 300. That determines the total amount of net free area needed to properly ventilate the attic. Calculate or enter the square footage of the attic or area to be vented.

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