I have a customer who has an original tiled Victorian hallway. In geometric quarry tiles. There is a section that has recently dropped and flexes when walked on. The two rooms that run next to the hallway have suspended timber floors. The section that has sunk sounds and feels like it could be on wood. Has anyone had any experience of this type of tile being installed over wood? The rest of the floor is solid and feels like concrete underfoot. Was hoping to try and lift some floor boards to investigate further. Any help would be great.