Eave Input Vent Area To Floor Square Ft Ratio

A 6 x 12 vent would equal 72 sq.

Eave input vent area to floor square ft ratio.

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. 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. 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.

Once attic square footage is known divide by 150 for the 1 150 ratio. Say the contractor is standing in front of a house that has an attic with 2 200 square feet. And this guideline you ll need a minimum of. Always have a balanced ventilation system.

Ventsure 4 foot strip heat moisture ridge vent with weather protector moisture barrier. 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. 1 square foot of nfva per 300 square feet of attic floor if a vapor barrier is installed on the ceiling below. 1 500 square feet.

30 lineal feet required. 1 100 square inches of intake net free area needed. This ratio is required for modern insulated homes. Determine the total net free area required.

40 x 25 1 000 square feet of attic area 2. If you have 3 000 square feet of attic space this equates to 20 square feet of ventilation needed. Based on your 1100 sq. The next step is to select a suitable exhaust vent and intake vent that fits the roof design for best performance and best aesthetics.

In no case should the amount of exhaust ventilation exceed the amount of intake ventilation. 150 6 6 square feet of total net free area 3. 2 200 2 1 100 square inches of exhaust net free area needed. 30 feet x 50 feet 1 500 square feet.

So in our example we will divide the 1 500 square feet by 300. 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. In divided by 144 equals an area of 0 5 sq. Remember the minimum area requirement when using a continuous system is a ratio of 1 300.

Ok so now we know the square footage of the attic area to be ventilated.