Ask Jon Eakes

Last Updated: Friday, October 15th, 1999, Created: Friday, October 15th, 1999

HOW DO I AVOID BLOCKING THE EVE VENTS WITH INSULATION?

Blocking the eve vents with the insulation is one of the most common causes of moisture problems in attics. The insulation should extend over the top of the outer wall and stop short of the vents, not touching the roof in such a way as to block air passages from the vents into the attic.

Batts of insulation can be carefully pushed over the top of the outside walls and stopped short of the vents, but it is easier to install baffles to ensure that they stop at the right place. For loose fill it is essential that you install baffles before pouring in the insulation.

Baffles can simply be pieces of plywood tacked into place beyond the exterior wall before the vents, and slanted parallel to the roof to allow a continuous protected air channel around the insulation. Easy-to-use commercial U-shaped baffles are available, made of either cardboard or plastic, that fit against the roof and create an air channel around the insulation. When using loose fill, the channels should extend a foot above the insulation to prevent air currents from moving the insulation into the air channels. When using batts, or batts on top of loose fill, the channels can extend to the top of the insulation. These commercial air channels are useful in a converted attic with knee walls when connecting the attic ventilation from the eave vent area behind the knee walls to the gable vent area above the ceiling.

Keywords: Attic, Insulation, Moisture, Soffit, Ventilation

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