A friend asked me to ask you fellows- they want to remove old square tiles from the kitchen- I am not sure what they are made of- 1960's (linoleum? asphalt?)?? They seem to be glued down with a black substance-tar?? They want to either put tile or wood flooring, but will have to even out the floor, as there is a 'hump' the length of the room. Would it be better to just do the new flooring over the old- but what about 'the hump'?? Thanks for your brains and experience!