So I would like to put recycled timber floors in my house that is being renovated. There was originally tiles that we had pulled up then we had the floors stripped. My problem is that the bathrooms and laundry floors have already been done and I'm told that by the time we put 18mm underlay then floor boards which are 19mm that the floor height will be 37mm which is 27mm higher than our tiled areas. Anyone have any ideas on how to get around the height difference?