An attic baffle is simply an item to regulate the flow of air aka required roof venting and impede it the insulation from interfering with each other.
How to make attic baffles.
Measure the distance between your rafters and purchase enough rafter vent baffles to install one over each soffit vent.
Baffles should fit snugly between your rafters and extend from just over the vent at the wall plate up the rafter.
Be careful of any roofing nails that may be sticking out of the rafters or bay.
They come in several widths so purchase the baffle that fits between your rafters.
When set into place and sealed with spray foam the vent baffles are insulated and air sealed.
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.
The book that helped us build and renovate.
Staple the edges into place with the staple gun making sure they are lined up correctly and securely.
Attic baffles how they work.
The picture below courtesy of the epa indoor airplus program which we provide builder verification services for helps show how the system works.
You will need a baffle for each space between the rafters.
Commercially made baffles can be purchased in 16 inch or 24 inch widths.
Fit each one snuggly in the bay with the bottom starting where the ceiling joist meets the roof rafter.