Toilet Flange Replacement and Wooden Sub-Flooring Repair

Part 1 of 2

If water has been leaking around the base of the toilet, it may have, over time, affected the sub-flooring, rotting the wood and causing mold damage in the house. In order to accurately determine the condition of the wooden sub-flooring, the toilet needs to be removed and the wax ring cleaned, so that the flange and wooden sub-flooring can be inspected closely.

During the original construction, ABS glue is applied to the toilet flange and it is inserted into the sewer inlet. The flange is then screwed into the wooden sub-flooring through the flange’s mounting holes. Hard flooring is then installed to the base of the sewer inlet, or carpet only to the base of the toilet. The wax ring is then installed and the toilet is mounted over the flange. When there is a prolonged exposure of water to this area, the flange can deteriorate and the wooden sub-flooring can rot out. This causes the flange to fail to work correctly.

There are two ways to repair the damaged flange depending on the condition of the sub-flooring. First, if the sub-flooring is still in good condition, then a flange repair ring can be installed over the top of the existing flange. The second way is to cut out the damaged flange and sub-flooring, and replace them both completely.

Flange and Sub-Flooring Inspection

To establish which of these techniques to use, the toilet flange and sub-flooring need to be inspected carefully. The wooden sub-flooring should be free of dry rot, mold, or any other moisture related conditions. If the sub-flooring is only wet, and the flange is in good condition, then allow it to dry out completely before re-mounting the toilet. If the sub-flooring is damaged and coming apart, then it should be cut out completely and replaced before the toilet is remounted. Next, inspect the toilet flange. The metal ring should not be rusted or have any corrosion present. The flange’s mounting channels should not be bent outward or appear broken. The flange itself must be securely mounted into the wooden sub-flooring.

Parts for Flange Repair

If the flange is the only item that needs to be replaced, then the following parts should be purchased at a hardware or plumbing supply store. The first part is a flange repair ring. The repair ring will only be effective if it is installed over undamaged sub-flooring. Damaged sub-flooring will not hold the repair ring tightly to the floor. Additional parts are some outside 1 1/2-inch deck screws, to secure the new flange to the wooden sub-flooring; a new wax ring that has a plastic lip; and toilet mounting bolts. Generally mounting bolts come included with the wax ring.

Project Repairs GuideGuide with Complete List of Parts Needed

Flange and Sub-Flooring Inspection

To establish which of these techniques to use, the toilet flange and sub-flooring need to be inspected carefully. The wooden sub-flooring should be free of dry rot, mold, or any other moisture related conditions. If the sub-flooring is only wet, and the flange is in good condition, then allow it to dry out completely before re-mounting the toilet. If the sub-flooring is damaged and coming apart, then it should be cut out completely and replaced before the toilet is remounted. Next, inspect the toilet flange. The metal ring should not be rusted or have any corrosion present. The flange’s mounting channels should not be bent outward or appear broken. The flange itself must be securely mounted into the wooden sub-flooring.