We had an extension 3 years ago. When it was done, our patio was extended as well. Since then, a corner of the patio has started sinking. Our garden is on a slant, so the patio is raised. It seems there probably isn't enough foundation underneath that section of the patio, so over time it's started to sink. It probably affects about 10 patio slabs, that will need to be lifted to strengthen the foundation. Quotes for the job are over £1000. We think the builder who did it should be responsible for it, but he says we have to pay (also over £1000) because it's over a year since the job was finished. But this seems like the work wasn't done properly and he should be responsible. All other builders we've had round to look have said that we should get a solicitor to write to our original builders to get them to cover it/fix it. We don't want to ruin our relationship with our original builders, but we also don't want to spend over £1000 on something because he didn't do it right to start with. We need opinions on whether something like this should be the responsibility of the original builders, 3 years after the job finished, or if we just need to accept that it's going to cost us to fix it.