Thanks for the reply. Just one more thing, after i put liquid dpm on the floor do i need to put sand on the L.dpm before i put the self levelling compound down or can i just put the self levelling compound down directly on top of the L.dpm.
It's not a good idea to put sand over the top of it. The sand could bridge between the floor and the dpm and allow damp to get through. Use a good neoprene primer like Balls P131 and the smoothing underlayment will bond just as well.