I had been wondering if we had a leak for a year or two as there was some swelling at the bottom of one of the cabinets next to the loo and under the sink but I put that down to having two young boys who like splashing. The last week our babysitter used our loo and caused a flood. Water was seeping up from around the base of the toilet. The leak did eventually stop and I called in a plumber who came yesterday (no rush as we have a downstairs loo).
The plumber said it was long-term slow leak on the flush pipe. He put soft putty about the flush pipe gromet to help in the medium term but it still seems to be very wet at the join and I think we may have to replace it instead.
The loo is a back-to-wall type in a unit that also has the sink. yesterday i discovered the cistern used wasn't put in a metal frame as it should have been. The back panel behind the loo has swollen so much that it can't be put back, and we shouldn't use the loo until it is replaced as it helps stablise the bowl.
The bathroom was put in 3 years ago. should I go after the original biulder to make good the damage, or is it too late? Unfortunately slow leaks aren't covered on my household insurance.