the builders have done a screed which had set before the put it down as the couldn't get access to the property, its like it hasn't bonded together properly and i can dig through it with my finger. I need to somehow seal the screed they have done they put a latex on top to build the area up, then put another coat on so everywhere is smooth before I put the lvt down. I was thinking a dpm would be good to try and get a better surface to screed on top of.
You can dig your finger through it and you now want to put another screed on top If its that soft then it needs to come up, no other way around it. Would you build a house straight ontop of sand??
I had a similar situation a couple of months ago, it was an extension, the builders screed was solid to walk on,but could easily dig through the full depth with a screwdriver, the builder didn't want to take it up again and said he would latex over it,so I said fine, but i won't be fitting anything on top,finally got the customer to get it asphalted, which worked out ok, because i was originally going to have to screed it twice, to bring it up to level
Had another builders screed problem, the screed had set solid, but wasn't attached to the floor, so it had started to crack and moved when you pressed down on it with your finger, anyway, after a lot of arguing with the builder, who said there was nothing wrong with it,they managed to get the screed manufacturer out, they drilled holes in it and poured setcrete into it,which is some sort of resin and it actually worked