Hi everyone, I am in the process of turning our old dining room into a chillout/music room for myself...And I have come across a problem, the floor was very uneven concrete , with lines of damp at even distances across the whole floor. After a few taps with the hammer it appears as though it has had some sort of screed approx. 5mm thick put over the probably original flagstones...Now I need to know what I need to do to waterproof and level the floor, as it is out of the question to dig it all out and lay it properly...But after reading various articles on the web I am confused as to which if any levelling compound is both flexible and waterproof. So all suggestions will be greatly received..