How to Reseal Kitchen Worktop Joins – DIY Guide
To reseal kitchen worktop joins, remove the old sealant completely, clean and dry the joint thoroughly, then apply a fresh bead of waterproof silicone sealant. Smooth with a wet finger and leave to cure for 24 hours before exposing to water. Total cost is typically £10–£25.
- Stanley knife or craft knife
- Sealant remover tool or silicone scraper
- Caulking gun
- Masking tape
- Cloth or lint-free rags
- Small paintbrush or sponge
- Waterproof kitchen silicone sealant
- Silicone sealant remover solution
- Methylated spirit or isopropyl alcohol
- Masking tape
- Washing-up liquid (for smoothing)
- Worktop joining bolt and jig (if re-jointing)
Step-by-Step Guide
Score and Remove the Old Sealant
Use a Stanley knife to score along both edges of the old sealant bead, cutting cleanly away from the worktop surface without gouging the material. Work the silicone scraper underneath and peel away as much as possible in one strip. Apply a silicone sealant remover solution to any stubborn residue, leave it for the time stated on the packaging, then scrape clean. Removing every trace of the old sealant is the single most important step — new silicone will not bond properly over old material. If your joint also has a physical gap or the worktop has shifted, this is the point to re-tighten the joining bolts underneath before you proceed.
Clean and Degrease the Joint
Wipe the entire joint area — both worktop faces and any upstand or wall behind — with a cloth dampened with methylated spirit or isopropyl alcohol. This removes grease, soap residue, and any invisible sealant remover film that would prevent adhesion. Allow the surface to dry completely; silicone applied to a damp or greasy surface will peel away within weeks. For laminate worktops in particular, pay close attention to the edge seam where water typically wicks in. Do not rush this stage — five minutes drying time prevents months of failed seals.
Mask the Joint for a Clean Finish
Apply masking tape along both sides of the joint, leaving a gap of 4–6 mm between the tape edges — this defines your finished sealant bead width. Press the tape down firmly at the edges so sealant cannot creep underneath. Neat masking tape lines are the difference between a professional-looking result and a smeared, ragged bead that collects dirt. Keep the tape run as straight as possible, using a steel rule as a guide if needed.
Apply the Silicone Sealant
Load the tube into a caulking gun and cut the nozzle tip at a 45-degree angle to produce a bead roughly 4–5 mm in diameter. Hold the gun at a consistent 45-degree angle to the joint and apply steady, even pressure as you draw along in one continuous pass — stopping mid-run causes lumps. Overfill very slightly; you will smooth it back. Use a kitchen-grade, mould-resistant silicone — standard bathroom silicone is not formulated for the heavier grease and cleaning agents found in kitchens. If you are sealing the joint where a worktop meets a tiled splashback, also read our guide on regrouting wall tiles to address any adjacent grout at the same time.
Smooth the Bead and Remove the Tape
Dip your fingertip in a solution of washing-up liquid and water — this stops the silicone sticking to your skin — and draw it along the bead in one smooth, firm stroke to tool the sealant into both surfaces and create a slightly concave profile. A concave bead sheds water rather than pooling it. Pull the masking tape away immediately, before the silicone skins over (usually within 5–10 minutes of application). Pull at a low angle, away from the bead, for the cleanest edge. Wipe any smears off the worktop surface with a damp cloth straight away.
Allow Full Cure Before Use
Leave the sealant undisturbed for a minimum of 24 hours before allowing any water contact, and 48 hours before normal use. Check the manufacturer’s data sheet on the tube — some kitchen silicones require longer cure times in cold or low-humidity conditions. Do not try to speed up curing with a heat gun; this causes surface skinning while the core remains wet, leading to premature cracking. Once cured, the sealant should feel firm and rubbery with no tacky spots. A correctly applied, fully cured seal should last 5–10 years before needing attention again — far longer than paint-on sealers or grout-based alternatives.
Frequently Asked Questions
How long does resealing a worktop joint take?
The active work — removing old sealant, cleaning, masking, and applying new silicone — takes around 1 to 2 hours. Factor in a minimum 24-hour curing period before the joint can get wet, so plan the job the evening before you need the kitchen back in full use.
Can I use bathroom silicone on a kitchen worktop joint?
It is better to use a silicone specifically labelled for kitchens. Kitchen-grade silicone is formulated to resist the higher levels of grease, detergents, and temperature fluctuation found around worktops. Bathroom silicone will work in the short term but tends to discolour and degrade faster in a kitchen environment.
How do I get rid of black mould under the old sealant?
Once the old sealant is removed, treat the surface with a dilute bleach solution (approximately 1 part bleach to 10 parts water), leave for 10 minutes, then rinse and allow to dry completely before resealing. If black mould has penetrated the substrate material itself — particularly on chipboard worktops — that section of worktop may need replacing rather than resealing. For advice on dealing with mould around grout and sealant lines, see our regrouting guide.
My worktop joint has a visible gap — can I just fill it with silicone?
A visible gap usually means the joining bolts underneath have loosened. Pull the sealant out, tighten the bolts to close the gap first, then reseal. Silicone alone will bridge a small gap temporarily but is not a structural fix — a gap wider than about 2 mm will allow the sealant bead to flex and split under normal worktop pressure. If you need guidance on working in the cabinet space below, our fix a sagging kitchen drawer guide explains how to access the underside of units safely.
How often should kitchen worktop joins be resealed?
A correctly applied kitchen silicone seal should last between 5 and 10 years under normal use. Check the joint annually — any discolouration, shrinkage away from the worktop surface, or visible cracking is a sign it needs replacing. Catching it early prevents water ingress into the chipboard substrate below, which swells irreversibly and is far more expensive to fix than a straightforward reseal. For broader maintenance advice, see our complete kitchen DIY guide.
When tooling the sealant bead, use the edge of an old credit card cut to a slight curve rather than your fingertip — it creates a more consistent concave profile and keeps the silicone off the edges of your tape. Keep a bucket of soapy water nearby and wet the card before each pass.
Sources
- Which? — How to reseal a bath or shower — which.co.uk
- HSE — Selecting suitable sealants and adhesives for workplace use — hse.gov.uk
- Gov.uk — Building regulations for kitchens and home improvements — gov.uk
This guide is for general information only. Always work safely and follow manufacturer instructions. DIYnut accepts no liability for injury or damage arising from DIY work.
