Strip out old bath sealant, clean the joint, then apply and smooth a neat new bead of sealant.
RB-01Prepare the roomOpen a window or door for ventilation, as sealant remover and fresh sealant both give off strong fumes. Clear anything from the bath and surrounding area, and lay an old towel on the floor to catch debris. Set out your tools so you're not hunting for them mid-job.
1 each · Old towels or dust sheet RB-02Cut out the old sealantRun a sharp craft knife or a dedicated sealant removal tool along both edges of the old bead, then peel it away in strips. Work slowly and keep the blade angled away from the bath surface and tile grout so you don't scratch or gouge them.
1 each · Craft knife or sealant removal tool RB-03Clean the jointWipe the whole joint with methylated spirit or a specialist silicone remover on a cloth to lift leftover residue, soap scum and any mould. Scrub gently at black mould spots and rinse the cloth often. Leave the joint to dry completely for a few hours, or overnight — any dampness will stop the new sealant sticking.
1 bottle · Methylated spirit or silicone sealant remover RB-04Mask off the jointOnce fully dry, run a strip of masking tape along the bath edge and another along the tile edge, leaving an even gap of around 5mm between them. This gives you a straight guide line and stops sealant smearing onto the tiles or bath.
RB-05Fill the bath with waterFill the bath about a third full with water before sealing. The weight pulls the bath down slightly to match how it sits when it's actually used, so the seal is less likely to crack later. This isn't essential but it's worth the extra ten minutes.
RB-06Load the sealant gunCut the sealant tube's nozzle tip at a 45° angle, sized to give roughly a 5mm bead. Pierce the foil seal inside the nozzle with a long thin tool or a piece of wire, then load the tube into the sealant gun.
1 tube · Bathroom mould-resistant silicone sealant RB-07Apply the new beadStarting at one end, squeeze the trigger with steady pressure and draw the gun along the joint in one continuous motion. Try not to stop partway, as restarting a bead often leaves a lump or gap. Keep the nozzle tip touching both surfaces as you go.
RB-08Smooth the beadWet your fingertip with soapy water, then run it along the bead once in a single smooth stroke to push the sealant into the joint and remove excess. Wipe your finger clean between strokes if you need more than one pass, but avoid going over the same section repeatedly.
1 splash · Washing up liquid RB-09Remove the masking tapePeel away both strips of masking tape straight away, before the sealant starts to skin over — usually within a few minutes. Pull the tape back on itself at a low angle so you don't drag or smudge the fresh bead.
RB-10Leave it to cureCheck the tube for exact curing times, but as a rule don't let water touch the sealant for 24 hours and avoid using the bath fully for 5-7 days while it cures completely. Drain the water you added earlier after a few hours, letting it out gently so it doesn't splash the new bead.
RB-11Tidy upWipe down the sealant gun nozzle and reseal the tube if there's any left for another job. Bag up the old sealant strips, used cloths and tape, and give the bathroom a final wipe-over. Keep the window open a little longer to help the fumes clear.
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