We have had a new kitchen fitted and to our horror have noticed that a mitred joint in the worktop close to an inset sink is starting to bubble up. I guess that this is due to water entering the joint causing the chipboard to swell. It would be very difficult to open up the joint to seal it. Is there anything I could run into the joint to at least stop the swelling getting any worse? As a wild thought what about WD40?
Thanks.