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Sealing & joints

Resealing a shower joint so it lasts

A reseal that fails within a year almost always failed at the start, before the cartridge was opened. Getting the old bead and its residue off is the slow half of this job and the half that decides whether the new one holds.

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Why removal matters more than application

Nothing sticks to a surface that has had silicone on it — including new silicone. A bead applied over the invisible oily film left by the old one is a bead that will peel in a season, and no amount of care with the nozzle changes that.

Getting it off

Cut the bead out with a sharp blade, working along both edges rather than tearing it. Then deal with the film: dedicated silicone removers soften it, and a solvent wipe afterwards takes what is left. Run a fingertip along the joint — if it feels slightly slick, it is not ready.

Then let it dry completely. A joint that has been wiped with anything wet needs hours, not minutes.

Choosing the cartridge

Sanitary grade, always. It carries a fungicide intended for permanently damp joints; ordinary construction silicone goes black at the edges within a season, and the growth is inside the bead where no cleaner reaches.

Then the chemistry:

  • Acetoxy — smells of vinegar, cures quickly, costs least. It can stain natural stone and marble and attack some metals.
  • Neutral cure — costs more and is what stone, marble and mirror backs need.
  • MS polymer — sticks to more, takes paint, and leaves no silicone residue, which makes the next reseal far easier.

Applying it

Mask both sides if you want a crisp line. Lay one continuous bead, then tool it once, within the skin time the maker states. Going back over a bead that has begun to skin is what produces the ridged, dragged finish people associate with a bad job. Pull the masking tape while the bead is still wet.

Then leave it alone

The full cure is considerably longer than the skin time, and the manufacturer states both. Using the shower before the bead has cured is the second commonest reason a reseal fails.

Questions people actually ask

Can I put new silicone over old silicone that is still sound?

It will not bond, and that is not a matter of degree. Even a sound old bead has to come out entirely if the new one is to hold.

What width should the bead be?

Wide enough to bridge the gap and no wider. Sealant makers publish a minimum and maximum joint width, and a bead outside that range fails by tearing rather than peeling — which is why an enormous bead is not a safe bead.

Last reviewed 5 September 2026

The equipment this assumes

Everything above works with what you already own. These are the products we would reach for, and each links to the full review rather than straight to a shop.