Method and apparatus for installing a rigid panel while maintaining a ventilation gap

A method for insulating a building having a flat structure supported on rafters, comprising the steps of:

• mounting first left and right brackets onto left and right rafters, respectively, each of said first left and right brackets including a pair of spacer legs, having a free end at a first elevation, an upper stop at a second elevation below the first elevation, and a lower stop at a third elevation below the second elevation, with the upper and lower stops of the left bracket projecting to the right and the upper and lower stops of the right bracket projecting to the left;
• at least one of said first left and right lower stops being movable;
• said brackets defining a ventilation gap distance extending from the first elevation to the second elevation;
• and then
• pushing a flat, rigid panel upwardly, between the first left bracket and the first right bracket, said flat, rigid panel being wider in the left-to-right direction than the left-to-right space between the first left and right upper stops, so that the upward movement of the rigid panel is stopped by the first left and right upper stops, wherein said step of pushing the rigid panel upwardly includes pushing the rigid panel upwardly past the respective movable first left and right lower stops with at least one of the first lower stops in a retracted position;
• and then
• moving the at least one movable lower stop to an extended position;
• and then releasing the rigid panel, whereby the first left and right lower stops limit the downward movement of the rigid panel after it is released, so the rigid panel is trapped between the respective upper and lower stops of the first left and right brackets.