Does My Attic Need More Ventilation

If you see dampness or frost you need better roof ventilation and some attic vents.

Does my attic need more ventilation. In other words the entire vent opening doesn t count as vented space. Because this type of fan blows so much hot air out of the attic it often requires additional intake ventilation to replace the air such as a gable vent on the opposite side of the attic. Of venting technically net free vent area or nfva for each 150 sq. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.

Roofing experts say the majority of u s. Solar fans are powered by the sun so they don t require electricity to operate. Why roof ventilation is a must for example attic ventilation is used widely even in cold climates to evacuate the warm moist air that escapes from the living space below. Homes do not have proper roof ventilation which can lead to severe roof damage.

If that air lingers it can cause condensation on the underside of the roof sheathing which can lead to wood rot and mold growth. In order to facilitate this exchange of warm and cool air the general rule of. In some circumstances you can have less but we recommend the 1 150 ratio. Taking advantage of this natural process referred to as passive ventilation is the most common way to vent an attic.

The federal housing administration recommends at least 1 square foot of ventilation for every 300 square feet of attic space. 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. The downside of attic ventilation fans. That said air resistance and interference such as vent grates reduces the area of true ventilation.

Enter square footage calculate or enter the square footage of the attic or area to be vented. Most building codes require 1 sq. Attic will need 10 sq. You can also contact your local municipality to check on building code in your area.

Grab a flashlight and inspect your attic during the winter. Hvi recommends a ratio of 60 to 40 for soffit ventilation to gable or ridge ventilation. Air flows in through the soffit vents and out through the roof vents. 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.

Of venting ideally about half placed high on the roof and half in the soffits. For the best results place roof ventilation near the roof s peak and soffit vents in the eaves.