Damp coming up through concrete floor

[Biggsy1980]

Hello
I’m in need of some help/advice. Currently doing up a 1950s bungalow. It had parquet floor which was all taken up to reveal the bitumen. We then had underfloor heating (wet system) installed. The company channelled groves into the floor. Our builder then put a layer of Ardex (I don’t know which one) over the top and then a latex screed (Uzim) over the top.
A few weeks passed when in three patches the flooring came up in ridges. The patches aren’t near external walls. I’ve attached a couple of photos pre and post removal of some the screed.

From research, I think the following has happened… the bitumen was acting as a DPC. The channels for the flooring have breached this and now damp is coming up.

Q1 - Am I on the right line
Q2 - Best way to fix it? Builder has just suggested patching it, the underfloor company have said to leave it and it’ll dry out eventually as the heating is sucking the moisture up and the latex company have said to take it all up!!!!
Q3 - Everyone is currently saying they’re not liable for the repairs. This seems like a common issue so surely something should’ve been put in place to prevent it???

Anyway, all/any help gratefully received
Cheers

 

[Old Salt]

I know nothing but in your situation I would leave it a few weeks to
a. See if it gets worse
b. See if it stops
c. Think about what to do next

So leave it to dry out, if not patch it, if that doesn't work take it all up.

You have nothing to lose by waiting a bit to see how it goes.

 

[accelerator]

My view - there are only two sources of water, either it's the underfloor heating leaking, or it's ground water coming up (if your floor sits on the ground and is not suspended).

The likely answer is that any DPC in the floor was breached, so what was waterproof isn't now.

 

[Biggsy1980]

We’re happy as we can be that the there isn’t a leak. The pressure for the underfloor heating hasn’t dropped and the patches did shrink during a dry spell but have gotten bigger now it’s raining a lot.