A Toilet That Rocks

A toilet sits on a soft seal that is compressed once, when the fixture is set down, and is not designed to flex afterwards. Every rock works that seal. The result is a leak at the base, and it arrives long after the movement started.

The instinct is to tighten the two bolts at the floor. On an uneven floor that does not stop the movement — it loads one point of a brittle ceramic fixture against a hard floor. Cracked bases are commonly cracked this way.

If the bolts turn without resisting, they are not the problem either: the flange they anchor to has broken or corroded, and no amount of tightening reaches it.

The flange is the ring that fixes the drain to the floor and holds the bolts. Cast iron ones corrode, plastic ones crack, and one that has been wet for a long time sits in a subfloor that has softened around it. A toilet bolted to a broken flange will move again whatever is done above it.

This is why a rocking toilet is worth someone looking at rather than adjusting: what needs fixing is under the fixture, and finding out means lifting it.

If the floor is level and the fixture rocks slightly on one corner, the gap can be shimmed and sealed. That is a real repair and a small one. It is also the only version of this that is small, which is why it is worth establishing whether the floor is sound before assuming it.