Kitchen mitre joint swelling after 4 weeks

Not sealed correctly

Hi Hayley! Swelling in a kitchen worktop mitre joint near the sink after a few weeks is usually caused by moisture getting into the joint. Here are some common reasons why this might happen: Possible Causes of Mitre Joint Swelling: Water Ingress: Even if the sink hasn’t been heavily used, small amounts of water or steam can seep into the joint if it’s not properly sealed. Poor Sealing: If the mitre joint wasn’t sealed correctly with waterproof sealant or adhesive, moisture can penetrate and cause swelling. Condensation or Steam: Kitchens generate moisture from cooking and washing, which might affect the joint over time, especially near sinks. Material Quality: Some worktops (especially laminate or MDF-based) are more susceptible to swelling when exposed to moisture. Joint Fit: If the mitre joint wasn’t tightly fitted or the adhesive has failed, moisture can enter more easily. How to Fix or Prevent: Check and re-seal the mitre joint with a good waterproof adhesive or silicone sealant designed for kitchens. Make sure the joint is clean and dry before resealing. If swelling is severe, you may need to replace or repair the affected section. Try to keep the area dry and wipe up spills immediately. Summary: Cause Solution Water ingress Properly seal joint with waterproof adhesive/sealant Poor sealing Clean and reseal Steam/condensation Improve ventilation, keep dry Material issues Consider upgrading material Loose joint fit Re-glue or repair joint

Even small amounts of moisture around the sink can cause swelling in laminate countertops, as they are usually made from moisture-sensitive chipboard. Proper biscuit joinery is important for the strength of the miter, and once installed, the area around the sink should be sealed with a waterproof, mildew-proof silicone to prevent water ingress.

Not sealed properly.

No sealant in the joint when fitted or sealant is damaged

I imagine the joint wasn't sealed properly and definitely taking in moisture. Not an easy fix 😕

Well I installed a laminate worktop sealed from factory and the factory sealed end was near sink and it started to swell after a few months. Ikea offered me another worktop so I said who is going to pay for the labour, they refused. Its not always straight forward but if you look at the joint carefully and see if there has been water penetration then you know what caused it. If you can't see the tell tale signs then it could be moisture that is emenating from appliance like dishwasher, etc.

More than likely the joiner/plumber hasn’t sealed around the sink using silicone or other sealant’s casing water to get under the laminated sheet on your kitchen worktop making it soak up the water and swell. Any more questions feel free to ask Thank you TC joinery

Swelling at a mitre joint after only a few weeks usually indicates moisture ingress. Even if the sink hasn’t been used much, steam, splashes, or condensation can find their way into the joint if it wasn’t properly sealed during installation.

Mitre joint not sealed correctly

it is not properly sealed !

More than likely the joint hasn’t been sealed at all or at most the correct manor

No sealant in the joint when fitted

Well its water .so either the worktop was wet when installed or it's a bad joint

We always seal edges then use colour fill along edges never had an issue can only guess it hasn’t been sealed costly mistake

As mentioned, the joint has not been sealed correctly. Dependant on the material used for your worktop as well, if this is solid wood and has not been treated correctly, moisture will also have this kind of negative affect.

Joint not sealed correctly

Definitely joint has not been sealed correctly

The jiont has not been sealed.

They have not sealed the joint properly.