How to Cover Rotting Wood Under a Toilet

Turn off water supply below the toilet tank, flush the toilet and disconnect pipe from toilet, also called a closet.

Wipe up any excess water that comes out of the supply pipe.

Lift the toilet from the floor and place it away from the work area, and stuff the drain hole with a rag to keep debris from falling in and block sewage vapors from leaking into the room.

Scrape any old wax or caulking from the bottom of the toilet around the hole, also called the horn.

Remove the old wax ring from the floor and inspect the flange, which is the metal ring attached to the floor that the toilet is bolted to.

Remove screws from old flange and slip the two pieces of the flange support under it, making sure that the support edges extend beyond the rotting wood.

Screw the flange support plates to the subfloor and drill pilot holes through the slots in the flange, starting with the slots closest to the closet bolt holes.

Place the new wax ring on the toilet horn and press firmly to create a tight seal.

Run a piece of masking tape on the floor in a straight line away from one of the closet bolts to make it easier to line the holes in the toilet base to them.

Lower toilet directly over the bolts, replace and tighten the nuts, replace nut covers, and reattach and turn on water supply.