Step 3 · Subfloor Assessment and Preparation
Now that the area is clear, thoroughly inspect the subfloor surrounding the drain pipe. Use a flashlight to look for signs of water damage, such as dark stains, discoloration, or delamination of plywood. Probe the wood with the tip of a utility knife or a screwdriver; if it feels soft, spongy, or crumbles, it has rotted and must be repaired. Assuming the subfloor is solid, ensure the surface is clean, dry, and free of any old sealant or debris to provide a flat, stable base for the new flange.