How To Vent An Old Attic

First determine your attic area by multiplying the length by the width.

How to vent an old attic.

The idea is that wind goes into one gable vent and then pushes the air out of the attic and through the secondary gable vent on the other side of the attic. Hole through the soffit right between the lines and measure the thickness of the soffit panel probably 1 4 or 3 8 in. Attic for example has an area of 1 200 sq. For this reason the square footage of vent space at the base of the roof and at the peak.

You can also contact your local municipality to check on building code in your area. Draw an outline for it on the soffit and cut the hole with a reciprocating saw. It must also circulate. The building code lets you reduce that by half under some conditions but more roof ventilation is usually better.

Most building codes require a ratio of 1 150 ventilation space to attic floor space. Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic. That said air resistance and interference such as vent grates reduces the area of true ventilation. Then aim for about 1 sq.

For proper ventilation it isn t enough for air to simply get into your attic. Begin by making sure your existing system works photos 1 and 3 plugging major air leaks into the attic photo 2 and correcting any other of the common causes of poor attic venting. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. Next bore a 3 4 or 1 in dia.

Generally speaking you need a ratio of 1 300 where for every 300 square feet of ceiling space you need 1 square foot of attic ventilation. Install a soffit vent by working outside the house. Cut the two parallel lines with a portable circular saw. Hot air exhaust vents located at the peak of the roof allow hot air to escape.

If those steps don t solve the problem add more soffit vents following the techniques we show in photos 4 17. Fit the vent in the hole and nail it to the soffit with. In other words the entire vent opening doesn t count as vented space. In of vent opening per 150 sq.