wet patches on kitchen floor levelled using sand / cement

Hi, The levelling compound shouldn't seal any moisture in Reasons for this could be there was a initial problem with the sub floor ie. breached Dom allowing damp though. Or The thicker the levelling compound the darker it dries, from your suggestion of using sand/cement I'm guessing there were some relevant deep areas to fill. So the damp looking areas could actually just be dark dry patches. Best way to find this out is to either use a moisture reader Or if you cannot get your hands on one of these then cut a 300 mm square piece of clear polythene and tape it over the damp patch if after a few hours there is moisture on this then you have a damp problem, if not, then that patch has just dried dark in colour. Hope this helps Andy