Cracked latex under new luxury vinyl tile

[tippytappy]

We had a new floor laid in July. It started lifting and buckling recently so the builder came to look at it yesterday. The latex they laid underneath the tiles is cracking. They're trying to help but say they don't know why it's happening. The latex went on top of the original concrete base. I'm pretty sure it would have been dry before they tiled over it, as they left it drying over a weekend.

Does anyone here know what might have caused this, and what we can do about it?

 

[DiyNutJob]

Probably temperature related expansion. I don't know anything about this latex. Can you not patch it up with more latex of the same?

 

[dazlight]

Damp in the sub floor , can see that from the picture.

 

[dazlight]

also could be contamination. What was sub floor and when was it laid.

 

[tippytappy]

Thanks dazlight. It's a concrete base. I don't know exactly when it was laid but it was there before we bought the place, so more than 14 years. They filled that gap yesterday and came back today to put the tiles back. But overnight more of the latex developed cracking and lifted too. They weren't sure, but also said they think it's damp. They suggest taking off the latex, then painting with some sort of damp-proof substance, laying a sheet membrane over that, then re-latexing and laying the tiles.

This floor replaced the laminate that was on when we bought, which showed no problems. So I wonder whether to go back to a laminate?

 

[dazlight]

Needs all removing then prob the concrete screed grinding clean. Then a liquid Dpm system. Loads of rules for doing this so it works. Most Bulider’s don’t use the right materials and put it down wrong.
You are better off with a latex screed then a water mix In most cases as well.
But the main way we do it is

ardex Na over clean screed
ardex DPM 1c
prime & ardex CL

or

Uzin PE404 , Uzin Gold screed

 

[tippytappy]

Thanks dazlight, that's brilliant. I'll pass that information on to the builders and see what they think. If they're not confident I'll look for someone else to do the damp-proofing, then get them back to re-lay the tiles.

Cheers.