I'm a DIY novice and looking for advice on how to lay a floor over concrete. Some years ago, the attached garage was converted to a kitchen. We recently had some water damage from a leak in the bathroom above it; the pipe connecting the bathroom sink to the wastepipe was leaking down the outside of the wastepipe and into our kitchen. It looks like the person who laid the current kitchen floor put down a plastic sheet (it's not a proper damp proof membrane, it's just a thin clear plastic sheet) over the concrete, then screwed 1" thick chipboard into the concrete and then put the laminate kitchen tiles on top of that. We're trying to do all of the work ourselves because we can't really afford to hire someone to do it but we want to make sure that we do a proper job of it. How do we sort out the kitchen floor? I assume that we need to put down damp proof membrane, how do we lay that properly? What do we put on top of it after that, chipboard?