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.
Roof ait flow baffle.
The picture below courtesy of the epa indoor airplus program which we provide builder verification services for helps show how the system works.
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.
Baffles establish a channel for air to circulate between the insulation and the roof sheathing.
The baffles make sure that the blown in insulation stays put so there s no wind washing.
When set into place and sealed with spray foam the vent baffles are insulated and air sealed.
The attic insulation baffles that we ll be installing will make sure that there s adequate air flow from the soffit vents.
As with attic floor insulation moisture and heat removal are the reasons for creating proper air.
That airflow is intended to churn the stale air in your attic which helps to remove moisture and control the temperature of your attic.
They will also allow us to maximize our blown in insulation without worrying about obstructing the air flow.
They are known are also known as wind baffle insulation baffles rafter vents or venting chutes.
They are usually made from cardboard or rigid foam board or polyvinyl chloride.