Hi there. We have recently had a laminate floor fitted, trusting the company involved (a local flooring firm) that the underlay we had chosen was suitable for our concrete floor. We asked for a silver-backed underlay, but XPS underlay was delivered and fitted on the day ("it's a better type of underlay" was what we were told. It rang true, price-wise, but we didn't know too much about it). With all the wood delivered and ready to go, we took their word for it. However, having done some research we are now reading everywhere that XPS underlay should always be fitted with a damp-proof membrane when it's going onto a concrete floor. With the floor now fitted, my question is as follows: Presuming that we should have a damp-proof membrane with XPS, is there anything we can do about it now? (I am considering paying for someone to untack the beading and pull up the flooring bit by bit in order to put a damp-proof membrane under there before relaying). The flooring is clicked into place (no glue), but the beading is glued in parts and tacked in parts too. I realise this is a novice question (I know I'm not a builder, but thought it would be OK to ask those who are!), but would appreciate any advice you could give. Thank you all.