How to Glue Foam Insulation to an Aluminum Patio Roof

Wash the aluminum with a solution of hot water and dishwashing soap. Once finished, rinse away all residual soap and leave the aluminum to dry.

Cut the tip of the nozzle from a cartridge of foam board adhesive at a 45-degree angle, using scissors. Poke a long nail down the inside of the nozzle to puncture the inner seal. Load the cartridge into a caulk gun.

Extrude a 1/4-inch bead of adhesive around the perimeter of one side of a board of rigid foam insulation. Extrude lines of zigzagging beads of adhesive across the inner area of the board. If the roof has ribs, apply the adhesive directly to the underside of the roof in a corner where the first board will go; apply the adhesive to the lowest portion of the ribs, where the aluminum will touch the board.

Press the board in place. Apply pressure all over to ensure a tight fit. Do not wait more than five minutes after extruding adhesive to stick the board, as the adhesive will start to set up.

Continue adhering boards in the same manner, fitting them tightly together. Cut boards to fit when necessary, using a saw or sharp knife. Mark cut lines, using a straightedge or T-square before cutting to ensure straight cuts.