Polycarbonate is a durable plastic used in a variety of products, including electronics, automotive components and construction. Like other plastic surfaces, polycarbonate is nonporous. This characteristic makes it a poor candidate for paint adhesion unless you precondition it using abrasion techniques. Before you paint your polycarbonate roof, employ the proper preparation steps or flaking will result. Apply the right coating, specifically formulated to resist sunlight and harsh weather elements, or the finish will ultimately fail.
Access your polycarbonate roof using an extension ladder.
Wash the roof using a pressure washer equipped with a low-pressure tip. Wait a full day for the polycarbonate to dry.
Abrade the polycarbonate to promote adhesion. Scour the roof with a palm sander stocked with 180-grit sandpaper. Stop when the plastic feels slightly rough.
Fill a 19 litre (5 gallon) bucket with no more than 7.6 litres (2 gallons) of acrylic latex primer. Attach the nap cover to the roller frame and screw on the roller extension pole.
Scale the ladder with the bucket of primer in hand. Set the bucket on the polycarbonate roof and descend the ladder to gather the roller and a 7.5 or 10 cm (3 or 4 inch) latex paintbrush.
Apply acrylic latex primer to the polycarbonate roof using the roller. Start at the far end of the roof. Roll vertically, working backwards in the direction of the ladder. Wait three hours for the polycarbonate to dry. Touchup any missed areas inaccessible to the roller using your paintbrush. Wait three hours for the primer to dry.
Clean each of your painting tools with water.
Apply exterior acrylic latex paint to the polycarbonate in the same manner as you did the primer.
Examine the safety guide on the side of the ladder before using it. Do not prime unabraded polycarbonate or the finish will flake. Never paint an unprimed polycarbonate roof or the paint will peel.