Do you seal the toilet to the floor?

Hygiene, not glue

The joint between ceramic and tile stops mop water, urine and dirt creeping under or behind, where you cannot clean. That is where the smell and the mould start. It also follows a little movement between a hard floor and the ware.

That does not make silicone a structural adhesive. A rocking pan is screwed or packed. A fat bead to hide a few millimetres of play fails as soon as someone sits: cohesion (tear through the middle) or adhesion (peel from the flank). A leaking waste collar is not “closed” with paste you can see.

Floor-standing and wall-hung

Floor-standing: yes, around the foot, continuous, so nothing creeps under.

Wall-hung: yes on the sides and top, with neutral sanitary silicone. At the bottom many of us leave 1–2 cm open. If the in-wall cistern drips, the water comes out where you can see it, not into the partition. Seal it all round and you lose that witness.

Not yet if the pan moves. Mechanics first.

How I do it

1. Check it is firm, with no play.
2. Strip all the old sealant. Degrease the flanks with a technical cleaner and a lint-free cloth.
3. On a wall-hung pan, if there is an acoustic mat behind, trim it to the outline of the ware so you do not bond on three faces.
4. Apply neutral sanitary silicone (OTTOSEAL S100 here), fill the meeting, tool a soft radius.
5. Let it cure. Keep water and weight off for the first day, depending on depth.

Do not use acrylic sealant around a WC: mop water eats it, it yellows and it grows mould. Do not gun fresh silicone over the old.

Mistakes I see

Uneven floor tiles: the bead goes from fat to a smear. The smear fails first. A cracked old joint: under the pan it rots what the cloth cannot reach.

Exceptions

An internal waste leak or a loose pan: plumbing, not more silicone. The witness gap on a wall-hung pan is trade habit, not a factory dogma; if the system wants it closed, close it, but then you have no visual warning.