How To Make Attic Baffles

Baffles should fit snugly between your rafters and extend from just over the vent at the wall plate up the rafter.

How to make attic baffles. Attach this roof and attic insulation treatment using foam baffles to ventilate insulate and channel cold and hot air to roof vents before insulation is add. You will need a baffle for each space between the rafters. Measure the distance between your rafters and purchase enough rafter vent baffles to install one over each soffit vent. Staple the edges into place with the staple gun making sure they are lined up correctly and securely.

Fit each one snuggly in the bay with the bottom starting where the ceiling joist meets the roof rafter. The rigid foam is cut to be 2 inches wider than the space between rafters then 1 inch of foam is scored and folded over on either side of the foam creating standoffs that hold the foam away from the roof sheathing providing a space for air to flow. They come in several widths so purchase the baffle that fits between your rafters. If your rafters are closer or farther apart than this distance it may be necessary to make your own rafter baffles.

The picture below courtesy of the epa indoor airplus program which we provide builder verification services for helps show how the system works. When set into place and sealed with spray foam the vent baffles are insulated and air sealed. Cut at least two 24 inch squares of inch plywood to use as seat boards when crawling out into the attic. Commercially made baffles can be purchased in 16 inch or 24 inch widths.

Be careful of any roofing nails that may be sticking out of the rafters or bay.