A neat, white bead along the bath looks simple. Getting one that stays neat and watertight is less so. Most failed DIY reseals come down to the same few problems: old sealant left behind, a damp joint, the wrong product, or a bath that was sealed empty.
This guide takes you through a proper reseal from start to finish. It’s written so you can do it yourself if you want to, and so you know what to expect if you’d rather have someone else do it. Set aside a good chunk of a day, plus time for the sealant to cure before anyone uses the bath.
Before you start: is it just the sealant?
Check that resealing will actually fix the problem:
- Does the bath move or creak when you stand in it? If so, it may need its feet or support adjusting first, or the new bead will tear.
- Are tiles near the bath loose or hollow? Water may already be behind them.
- Is there damp under the bath or on the ceiling below? A leaking waste or overflow can look like a sealant leak.
If the bath is solid and the problem is a split, shrunken or mouldy bead, a reseal is the right fix. Pick a day when nobody needs the bath for at least a day afterwards, and when you can keep the room warm and ventilated so the joint dries quickly before sealing and the sealant cures well afterwards.
What you’ll need
- Sealant removal tool, sharp blade and plastic scraper.
- Silicone remover product for the leftover film.
- Mould remover, a cleaning cloth and a suitable solvent cleaner for degreasing.
- Anti-fungal sanitary silicone in the colour you want. Everbuild and Arbosil both make sanitary silicones.
- A sealant gun.
- Masking tape (optional, but helpful for a neat line).
- A smoothing tool or spatula.
- Dust sheet, gloves and a bin bag.
Don’t use decorators’ caulk or a general-purpose sealant around a bath.
Step by step
- Remove all of the old sealant. Cut along the top and bottom edges of the bead, pull out the bulk, then take off the remaining film with remover and a plastic scraper. New silicone won’t bond to old silicone, so nothing should be left.
- Clean and degrease. Clean the bath edge and tiles, then wipe the joint with a solvent cleaner to remove soap and grease.
- Treat any mould. Apply mould remover to any staining in the joint, leave it as the label says, rinse and wipe.
- Let it dry completely. This can take hours, longer in a cold room. Run the fan or open a window. Don’t seal a damp joint.
- Fill the bath with water. This lowers the bath to its loaded position, so the bead isn’t stretched later. Everbuild’s Forever White data sheet says to fill the bath half full while sealing and during cure.
- Mask the joint (optional). Run tape along the tile and the bath, leaving an even gap for the bead.
- Apply the sealant. Cut the nozzle at an angle, a little smaller than the gap. Push the bead into the joint in one steady movement, keeping the gun moving at an even speed.
- Tool it. Smooth the bead with a tool or spatula in one pass, pressing it into the joint. Remove the tape straight away, pulling it away from the bead.
- Leave it to cure. Keep the water in the bath. Don’t use the bath until the sealant has cured.
How long before you can use the bath
Most silicones are touch-dry quite quickly, but that isn’t the same as cured. Everbuild’s Forever White data sheet gives a skin time of about 15–20 minutes and a cure rate of about 2–3 mm in 24 hours at 23°C and 50% humidity. In a cold bathroom, or with a thick bead, it takes longer.
As a rule, leave it around 24 hours before it gets wet, and follow the instructions on the product you used. Checkatrade’s bath reseal guide says standard silicone typically needs 24 to 48 hours to fully cure. Our guide on how long to wait before using the shower covers this in more detail.
Need it done properly? Mr Mastic covers the South East, London and Scotland, with a one-year guarantee on every job. Call or email for a quick quote.
Mistakes that cause leaks and mould
- Sealing over old sealant. It won’t bond and will lift. See why you can’t seal over old silicone.
- Sealing a damp joint. The bead looks fine and then peels.
- Sealing the bath empty. The bead tears the first time the bath is filled.
- Using too much sealant. A thick bead is harder to tool, collects dirt and doesn’t seal better.
- Going back over it. Tooling a bead several times drags the sealant and leaves ridges.
- Using it too soon. Water on uncured sealant can spoil the surface and the bond.
- Scratching the bath. Metal blades held at an angle mark acrylic baths.
DIY or professional: how to decide
| DIY | Professional | |
|---|---|---|
| Best for | A single bath with a clean, single bead to replace | Over-sealed, mouldy or repeatedly failing joints; several rooms |
| Tools | Buy the basics | Supplied |
| Time | Most of a day including drying, plus cure time | Usually a couple of hours for a single bath, plus cure time |
| Finish | Depends on practice | Neat, even bead |
| If it fails | You redo it | Covered by the installer’s guarantee (ours is one year) |
When to call a pro
- The old sealant is in layers or won’t come away.
- Mould is behind the bead or has spread to the wall.
- The bath moves, or there are signs of a leak below.
- You’ve resealed it before and it keeps failing.
- The bath is in a rental property, hotel or commercial washroom where the finish needs to be right first time.
Our bathroom resealing service covers baths, showers, basins, wet rooms and kitchen worktops. We cut out every bit of the old sealant, clean and treat the joint, fill the bath and lay a single, even bead of anti-fungal silicone.
Aftercare
Once the sealant has cured, a few habits help it stay white and watertight:
- Ventilate the bathroom during and after baths and showers.
- Rinse soap and shampoo off the sealant.
- Clean weekly with a mild, non-abrasive cleaner.
- Avoid scouring pads and harsh powders on the bead.
- Keep an eye on the corners, where gaps tend to open first.
- If the bead starts to lift, deal with it early rather than letting water get behind it.
Quick answers
Should the bath be full of water when resealing?
Yes. Filling it lowers the bath to its loaded position, so the bead isn’t stretched when the bath is used. Everbuild says to fill it half full while sealing and during cure.
Can I reseal a bath without removing the old silicone?
No. New silicone won’t bond to old silicone and will lift.
What sealant should I use around a bath?
An anti-fungal sanitary silicone. Not decorators’ caulk or a general-purpose sealant.
How long does it take a professional to reseal a bath?
Usually a couple of hours including removing the old sealant, then time to cure before use.
How long should I wait before using the bath?
Usually around 24 hours, or as the product’s instructions say.
Related services
More advice
- Can You Put New Silicone Over Old Silicone?
- How to Remove Old Silicone Sealant
- How Long After Sealing Can I Use the Shower?
- How Much Does a Mastic Man Cost? UK Guide
- All advice
This guide is general information about sealant work. It isn’t legal, fire-safety or structural advice; for those, speak to a qualified professional.