Slate tile is a natural surface composed of clay and rock. It is one of the worst candidates for paint adhesion, and if you attempt to paint your slate with ordinary acrylic or oil-based paint, you'll see significant chipping and peeling within weeks of application. Whether you need to paint existing slate tile on your roof, or on interior or exterior flooring, select a specialised coating specifically formulated for clay, concrete, and other natural surfaces, or you will end up with disappointing results.
Climb onto the roof, using an extension ladder.
Clean the existing slate, using a pressure washer. Wash the tiles at the far edge of the roof first and work backward, moving in the direction of the extension ladder. Allow the roof to dry.
Apply a coat of Rust-Oleum primer 44, using a latex paintbrush. Paint the tiles at the far edge of the roof first and work backward, moving in the direction of the extension ladder. Allow the primer to dry for four hours.
Apply a coat of Rust-Oleum Dac-Hydro in the same way you did the primer.
Work on a warm, dry day. You can paint slate flooring in the same manner as you would a roof. However, if you are working indoors, use a mop and bucket in place of a pressure washer. Rust-Oleum Dac-Hydro and Rust-Oleum primer 44 are ideal for coating slate tiles. If you choose a different brand, ensure that it is specifically formulated to coat slate or the finish will flake and peel soon after application.
Always work on the tiles located at far edge of the roof, first, and work backward, moving in the direction of the extension ladder, or you may trap yourself within wet paint.