Inspired by a helpful YouTube guide. We based this walk-through on the popular UK video "How to seal a bath", from B&Q, the UK DIY retailer. It's a clear, practical guide that covers the prep work well, which is the bit most people rush and then regret.
1. Gather what you need
You will need a silicone sealant remover tool (a Stanley knife and an old chisel also work), white spirit or IPA for cleaning, masking tape, a tube of bathroom silicone (mould-resistant if possible), a sealant gun, and a wet finger or a sealant smoothing tool for finishing.
Use a silicone designed for bathrooms, not a general-purpose one. Bathroom silicone stays flexible under movement, tolerates constant moisture, and resists mould better. You can get it at any DIY shop for a few pounds.
2. Fill the bath with water first
This is the step that catches people out. A bath flexes slightly under the weight of water. If you apply sealant to an empty bath, it will set in a relaxed position, then stretch and crack the first time someone gets in.
Fill the bath to roughly half full before you do anything else. Leave it full throughout the job and do not drain it until the sealant has fully cured, usually 24 hours. It sounds odd but it makes a real difference to how long the seal lasts.
3. Cut out all the old sealant
Work your way along the joint with a sealant remover tool or a sharp Stanley knife. Get as much off as possible. Pull away the loosened strips and scrape the surfaces clean.
Take your time here. Any old sealant left behind will stop the new silicone bonding properly and you will end up with gaps. A sealant remover tool with a hooked blade makes this job much easier than a knife alone.
4. Clean the joint thoroughly
Wipe both the tile surface and the bath rim with white spirit or IPA to remove soap scum, grease, and any remaining sealant residue. Let it dry completely before moving on.
If there is mould staining on the tiles or the bath, treat it with a mould remover spray and rinse it off before cleaning with white spirit. Starting on a clean, dry, grease-free surface is what makes the new sealant last.
5. Apply masking tape either side of the joint
Run a strip of masking tape along the tile, about 5mm above the joint, and another along the bath rim, about 5mm below it. This gives you a neat straight line to work to and keeps the surrounding surfaces clean.
Press the tape edges down firmly so the silicone cannot bleed underneath. The gap between the two tape lines is where your bead of sealant will sit.
6. Apply the new silicone sealant
Load the tube into your sealant gun and snip the nozzle at a 45-degree angle to give a nozzle opening slightly wider than the joint. Start at one end and run a continuous bead along the full length without stopping. Keep an even pace and consistent pressure so the bead stays roughly the same thickness throughout.
Do not be tempted to go back and add more halfway. One smooth pass is better than several overlapping ones.
7. Smooth, peel the tape, and leave to cure
Dip your fingertip in water (some people use a little washing-up liquid on a damp finger to stop it sticking) and draw it firmly along the bead in one stroke. This pushes the silicone into the joint and leaves a concave finish.
Peel off the masking tape immediately, before the silicone skins over. Pull it back at a low angle rather than straight up. Leave the bath full for 24 hours, then drain and leave it unused for a further 24 if you can. The silicone needs that full cure time before it gets wet.
When to call a handyman
Call Richard if the gap between the bath and the tiles has opened up because the bath itself is moving, if the wall tiles are cracked around the joint, or if water has already got behind the tiles and you can feel soft or hollow plasterboard. Those are bigger jobs than a simple reseal.
Need a bath resealed?
The Sandwich Handyman can reseal baths, showers, and basins in properties across Sandwich, Deal, and nearby East Kent villages. A neat, lasting seal that won't go black in six months.
Contact Richard