Updated
Worktop Joint Opening Up
The join between two lengths of worktop has opened into a visible line, and water sits in it after washing up.
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What's happening?
A worktop join is a butt-and-scribe or mason's mitre cut, pulled together underneath by bolts in routed slots and made watertight by a bead of jointing compound between the two faces. It relies on three things at once: the two cut faces meeting cleanly, the bolts staying tight, and the sealant staying bonded. Lose any one and the join opens. EGGER's guidance is that the compound is applied along the cut edges to create a watertight seal, and that their ten-year guarantee only holds where the specified sealing adhesive and fitting guide have been used. An open join in a laminate worktop is not just cosmetic — it is a route for water into the chipboard core, and once the core swells the top cannot be closed up again.
What usually causes it?
- Jointing bolts never fully tightened, or backed off as the base units settled
- The join made without jointing compound, or with ordinary silicone rather than a worktop jointing adhesive
- Base units out of level, so the two lengths meet at slightly different heights and the join is under strain
- A cut face that was not accurate, leaving the sealant filling a gap rather than bonding two faces
- Water sitting in the join after washing up, breaking the bond from the surface down
- Heat from a nearby hob, kettle or dishwasher vent drying and shrinking the laminate around the join
- The worktop screwed hard to the units with no allowance for movement, so the strain goes into the join
Is it dangerous?
No. It is a damage problem rather than a safety one, but it is a fast-moving one: once water is reaching the chipboard core the swelling is permanent, and a worktop that could have been re-jointed in an afternoon becomes a replacement length.
Can I fix it myself?
Look underneath first. The jointing bolts sit in routed slots on the underside, usually reachable from inside the base unit, and if they have simply worked loose they can be nipped up. That is the whole of the safe DIY here. Do not run silicone into the top of an open join — it seals the visible line while water carries on getting in behind it, and it makes a proper re-joint messier later. Keep water off the join and dry it after every wash-up until it is fixed.
When should you call a kitchen fitter?
Call a kitchen fitter when tightening the bolts does not close the join, when there is any swelling or dark staining along the join line, when the two lengths sit at different heights, or when a hob or a sink sits close to the join. Re-jointing means releasing the top, cleaning both faces back to bare material and re-bonding, which needs the join taken apart properly rather than filled.
What will the kitchen fitter actually do?
- Check the base units for level and pack them where the two lengths meet at different heights
- Release the jointing bolts and separate the join, cleaning old compound off both cut faces
- Inspect the chipboard core for swelling and advise honestly whether the length can be re-used
- Re-seal the cut faces and the join with a worktop jointing compound, then pull up and align the bolts
- Re-seal the back edge and any cut-out edges, and re-fix the top allowing for movement
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