Preparing a deck for clay tile roofing requires careful attention to the surface beneath the tiles to ensure durability and avoid issues like cracking or slipping. The deck should be sheathed with a solid, flat surface such as high-quality plywood or oriented strand board (OSB) that is rated for roof decking. This sheathing must be securely fastened to the roof framing using corrosion-resistant nails or screws designed for roofing applications to prevent movement over time. Flatness is critical because clay tiles don’t flex much, and any dips or bumps in the deck can cause the tiles to crack or shift. A good rule of thumb is to check the flatness by running a straightedge across the deck; any gaps greater than 1/8 inch over 6 feet should be corrected by sanding down high spots or shimming low spots. This ensures the clay tiles will sit evenly and stay securely in place throughout their long lifespan.
Some safe DIY checks before tile installation include inspecting that the deck is dry, clean, and free of any loose or damaged sections. Make sure all fasteners are flush with or slightly countersunk into the sheathing to avoid interference under the underlayment and tiles. It’s generally best to call a professional roofer if you find signs of rot or if the deck surface is uneven beyond minor corrections. When consulting with your contractor, ask specifically what type and thickness of sheathing material they recommend for clay tile and how they ensure the deck flatness before tile installation. Also, inquire about their fastening technique to confirm it meets code requirements and doesn’t risk voiding the tile manufacturer’s warranty. This helps avoid costly repairs and ensures the roofing system performs well over time.