How to Add a Plastic Roof to a Carport

Measure the width and depth of the carport with a measuring tape. The measurements will help you estimate how many roofing sheets you will need to complete the project.

Place the first plastic sheet on the carport frame along the end farthest from the house, which is the lower end of the roof. The sheet should be oriented vertically. Allow about 1/2 inch of overhang at the edges of the roof.

Drill holes through the plastic into the frame along the joists at 4-inch intervals. Place a flexible sealing ring over each hole. Insert and tighten 2-inch screws through the rings and plastic roofing into the frame, using a screwdriver.

Snip the tip of a caulk tube at a 45-degree angle with scissors. Load the tube into a caulk gun and depress the trigger. Apply caulk to the edges of the corrugated plastic sheet where the next sheet will overlap.

Place a second plastic sheet next to the first, overlapping the first sheet by one corrugation. Repeat the process of drilling holes and installing sealing rings and screws to secure the sheet to the frame. Repeat this process until the first row is completed, ensuring that the sheets extend beyond the edges of the roof by 1/2 inch. If a second row is needed, overlap the first row by 12 inches. Use a reciprocating saw to cut sheets as necessary to fit. Continue installing sheets until the roof is covered.

Cut a section of metal flashing to the width of the carport, using metal shears. Bend the flashing into an L-shape and place it where the carport meets the house. Drill holes, place sealing rings over the holes, and insert 2-inch screws to secure the flashing to the side of the house and the carport frame.

Apply a bead of caulk along the edges of the flashing.