My wife and I have sanded off the stained varnish from our pine paraquet floor and applied a clear varnish back on to make the room lighter. We also in the process had our old gas fire taken out, leaving the original concrete hearth. We now want to put some laminate flooring over this area (only about 0.8M2) to hide this area. We need to lower the hearth as it projects a few mm above the existing floor. Is it a case of just using brute force with a steel chisel and a lump hammer and finishing off with a leveling compound? Any suggestions?