How to repair a 'loose toilet'

Q: I'm trying to sell my home, and the potential buyer asked for a home inspection. One of the requested fixes was "a loose toilet." I tried moving the tank, but it is very secure. Do you have any idea what the home inspector was talking about? I want to make the repairs myself because I am already losing money on the sale.

A: This problem is quite common. The home inspector was discussing the loose toilet bowl where it is attached to the floor. The toilet bowl has a wax ring that seals it to the plastic or metal sewer drain, which is attached to the floor of the bathroom. There are two I-bolts that are used to secure the porcelain bowl of the toilet to the sewer ring on the bathroom floor. If the bolts are not tight or if they become loose, the bowl, not the tank, will rock back and forth and the wax seal may start to leak. The leak may be gradual, but over time the slow seepage can lead to structural damage in the flooring in the bathroom. Your first hint that something is wrong would be the toilet starting to lean off-center.

Possible reasons the I-bolts are not tight: 1) The flooring may be uneven, and a tight seal cannot be made using the two I-bolts; 2) the plumber or installer did not tighten the I-bolts when the toilet was installed; 3) the installer may have worried about cracking the porcelain bowl if the bolts were too tight; and 4) over time, the wood floor expanded due to moisture from the bath, and the I-bolts are now loose.

It is possible to crack the expensive toilet bowl by tightening the I-bolts. One remedy is to install plastic shims, available at hardware and home stores, to secure the bowl. Or you can use silicone caulk to fill smaller voids between the rim of the bowl and the floor. Once the repairs have been made, stand facing the toilet tank and place one knee on either side of the tank. Try to rock the bowl with your knees to see if it is secure. If not, start all over or contact a licensed plumber.

Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. Write to him with home-improvement questions at d.Barnett@insightbb.com. Sorry, no personal replies.