Patent ID: 8733064

Claim:
A method for installing a baffle in a building having an attic defined by: a vertical exterior wall having a horizontal top wall plate; parallel floor joists supported by said top wall plate; and spaced apart, inclined roof rafters securely connected to said top wall plate and said floor joists, said roof rafters having a roof covering fastened on their upper surface; said attic having a vent around its outer periphery between said top wall plate and the underside of said roof covering enabling the flow of ventilating air between an exterior soffit and insulating material installed between said floor joists in the interior of said attic, the method comprising: supplying to the building a rectangular panel from a sheet of an extruded cellular plastics material defined by a first upper wall, a parallel second lower wall and a plurality of parallel webs separating the first and second walls to create parallel hollow cells along the panel, the panel having first and second side edges, a top edge and a bottom edge; forming first and second parallel grooves in the sheet by cutting through the first upper wall at positions adjacent the respective first and second side edges of the panel; forming first and second side flaps of the panel by bending downwardly said first and second side edges of said panel respectively at said first and second grooves; forming a first V-shaped cut-out in the first side flap with an apex of the first V-shaped cut out being located at the first groove and with sides of the first V-shaped cut out diverging outwardly from the apex at the first groove to intersect the first side edge; forming a second V-shaped cut-out in the second side flap with an apex of the second V-shaped cut out being located at the second groove and with sides of the second V-shaped cut out diverging outwardly from the apex at the second groove to intersect the second side edge; forming a bottom flap of the panel by bending downwardly the bottom edge of the panel along a fold line, where the fold line extends at right angles to said first and second grooves and joins said apexes of the said first and second cut-outs; installing said baffle between adjacent roof rafters by locating said panel between said roof rafters with said bottom edge engaging the top wall plate and with said first and second side flaps extending downwardly along the roof rafters so that the first and second side edges are spaced downwardly from the roof covering; and attaching said first and second side flaps to respective inner faces of said roof rafters to block the flow of ventilating air through said insulating material.