Hello. The 10.5m² front hall of my 1968 house has a sub-floor of floorboards laid directly on concrete! (There is some polystyrene insulation below the concrete). This is the only room with floorboards-on-concrete, the rest are suspended floors apart from the back passage and downstairs loo which have concrete sub-floors. (Existing floor is carpet, as will the new floor.) Even though they're in good condition I'm thinking of removing the floorboards because they make a little bit of movement noise underfoot (existing carpet and underlay still on). From top of floorboards to concrete is about 21mm on average (I can't explain this dimension as I would have expected the floorboards to be 7/8".) What would be the best way to raise the sub-floor to around the existing height if the floorboards are removed? (I will be employing someone to do it, it won't be a DIY job.) Thanks in advance.
Is it clean concrete underneath. Prob won’t have a Dpm at that age. Ardex NA or similar with granno chipping to build up
