Vent Attic With Blocking Vents

Attic ventilation is a two part process.

Vent attic with blocking vents.

Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Blocked soffit vents invites attic or roof cavity moisture condensation mold the photograph at page top shows an attic whose intake venting is blocked by fiberglass insulation. Install them by cutting holes into the blocking between the exposed rafter tails and pressing the vents into the holes. The photograph at left shows severe mold on the underside of roof sheathing in a 1920 s cape cod attic where there was no under roof ventilation.

The soffit vents are now installed but you still need to make sure there s no insulation blocking the new vents. Diameters are ideal if you have eaves but no soffits. Available at roofing supply stores and well stocked home centers. If the attic is insulated with fiberglass batts just pull back any that are blocking the flow of air.

And many homes with terrible attic ventilation are completely mold free. First air enters through the soffit vents. The minimum recommended attic ventilation is 1 5 of your attic floor space. Nope venting an attic is actually pretty hard here s how ventilation is supposed to work.

If there s blown in insulation like ours rake back the fluffy stuff with a 3 or 4 ft long 1 x 6 or use a garden rake or hoe. These vents available in 2 3 and 4 in. Make sure the airflow has a clear pathway through the insulation.