We noticed the kitchen floor was damp under the cupboards when the kick boards were removed and from the damp pattern it seemed to spreading from the corner. Upon checking we thought the problem was the sink as at the same time we noticed it had a small leak, so we replaced this. This had no effect on the issue. We then investigated the kitchen drainage, upon camera inspection the drain had collapsed near our boundary near the corner of the kitchen with the issue.
We contacted our insurers, who got the collapsed drain repaired and arranged for some professional drying. Using this for a couple of weeks reduced the moister readings from 100% to below 15%. Stopped for 10 days, took new readings and the moister was back to 90%. The insurers then sent out some leak detection experts to look for a leak. After doing various gas tests/ dye tests etc. They concluded there is no leak and advised more drying. The dryers came back and again moister went from 100% to below 15%. Checked again 10 days later and back to 90+%.
The dryers said nothing they could do as it seems an ongoing problem and will report back to insurers. The insurers have come back saying - they have looked at everything and as they cannot establish the reason for the damp i.e. no insurable reason visible. It is down to us to do more investigation to find the cause. But if we find something to go back to them.
I have asked them for all reports they would have received from their contractors. To me I thought it was obvious the issue was caused by the collapsed drain in that corner of the kitchen, as we don't know how long it has been collapsed.
So any advise on how to proceed or who to talk to.