Step 1 Prepare Subfloor
The quality of your finished ceramic tile project depends on the quality of the surface beneath it. Before starting, remove any existing ceramic tiles and ensure your floor is flat and strong enough to meet industry standards (two layers of plywood totalling 1 1/4-inch thickness).
Smooth out hollows and valleys with self-leveling underlayment and/or reduce the height your installation by using plywood alternatives (Ex. 1/4-inch WonderBoard or 5mm EasyMat). Consider applying a waterproofing and anti-fracture membrane where needed for moisture protection or to prevent tile or stone from cracking.