Seal around the base of a toilet

Remove old sealant from a toilet's base, clean up, then apply a fresh bead to stop water and draughts.

TB-01Open a window and gather your toolsSealant fumes are strong in a small bathroom, so open a window or door before you start. Lay out your sealant remover tool or a sharp utility knife, cloth, methylated spirits, masking tape and the new tube of sanitary sealant. Wear disposable gloves — old sealant and mould can be grim to handle.

1 pair · Disposable gloves

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TB-02Cut away the old sealantRun a sealant removal tool or the tip of a utility knife along the old bead where the toilet meets the floor, and up the wall if it was sealed there too. Peel the old sealant away in strips rather than scraping — it comes off cleaner and you're less likely to scratch the pan or the floor. Take your time near the back of the pan where access is tight.

1 each · Sealant removal tool or utility knife

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TB-03Clean the joint thoroughlyWipe the whole area with a cloth dampened with methylated spirits to lift any last traces of old sealant, soap scum and mould. Let it dry fully — sealant will not stick to a damp surface. This usually only takes a few minutes in a ventilated room.

250 ml · Methylated spirits

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1 each · Cloth

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TB-04Mask off for a neat lineStick a strip of masking tape along the floor and another up the pan, leaving a clean gap the width you want the new bead to be — around 5mm is normal. Masking takes a bit longer but gives a far neater finish than trying to freehand it.

1 roll · Masking tape

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TB-05Apply the new bead, but leave a small gap at the backLoad the sealant gun and run a steady bead where the pan meets the floor, following your masking lines. Leave a short section unsealed at the very back of the pan, about 20-30mm — this isn't a building rule, but it's good practice. If the pan-to-floor joint ever leaks, an open gap lets you see the water straight away instead of it soaking into the floor unseen under a full seal.

1 tube · Sanitary silicone sealant (mould-resistant)

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1 each · Sealant gun

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TB-06Tool the bead smoothDip a finger in a little water or washing-up liquid and run it once along the bead in a single smooth stroke to shape it. Don't go back over the same spot twice or it will drag and look messy.

TB-07Remove the tape while the sealant is still wetPeel off the masking tape straight away, before the sealant skins over, pulling it away from the bead at a shallow angle. This gives you a crisp, straight edge without disturbing the fresh sealant.

TB-08Leave it to cure and tidy upCheck the tube for the curing time — most sanitary sealants need at least 12-24 hours before you can use the toilet normally, and longer before the room can steam up. Wipe your tools clean with methylated spirits before the sealant sets on them, and bin the offcuts of old sealant and used tape.

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