Hi All, I'm planning to put in engineered wood flooring in a 1930s terraced house. All of the floors are currently carpet over floorboards. To provide the proper subfloor/level surface for gluing it down, is it better to: Take up the floorboards entirely and replace with 18mm ply? Lay 6mm ply on top of the floorboards? Total buildup is a concern, as the flooring is 21mm.
I am not an expert but I absolutely would not take the floorboards out. Unless the boards are rotten or so seriously damaged that you have no other option, you should keep them.