I have just bought a house that had a continuous engineered oak flooring downstairs. There was an obvious buckle in the floor in the hall, at the centre of the house that we were told by surveyor/builder was due to poor fitting as expansion gaps had not been left between rooms.
This made sense as the position of the buckle was the juncture of flooring that spanned the entire length and width of the house (see attached plan).
Yesterday, our flooring fitter removed the engineered flooring in the hall to discover that the buckle was caused by what appears to be oak parquet flooring that was water damaged. In fact, there was a puddle of water on top of the parquet flooring where the buckle was.
We removed all the parquet flooring, and although one plank in the region of the buckle was slightly damp, with some sort of green moss growing on it, the rest of the planks were quite dry, with signs of having been previously water damaged. The concrete underneath the parquet flooring was bone dry, and the batons it attached to showed no signs of significant rot.
Currently our best guess is that condensation has caused this problem, however no one can explain what caused it. Currently, we are thinking our best course of action would be to fit ply in the void left by the parquet flooring to bring up the floor level, so the engineered floor can be re-layed. If, however, we did this, wouldn't we have the same condensation problem? assuming that was the cause.
This has got all our professionals stumped, so I was looking for some guidance please.