DPM issues over terracotta

[gamma38]

Hi all, I went to look at a job yesterday which the ex tiler walked from. The issues are, he has laid some slc on top of part new screed and part existing flooring which was terracotta tiles. This has been down for approx 8 weeks, not done very well i will add. They want to lay modular limestone. However the previous so called tiler just laid on top of the terracotta without thinking things through, no dpm and the damp is just coming straight through. Obviously i can't lay on this, I called ultra technical today to ask about there DPM it. Not suitable to withstand hydrostatic pressure was the reply. He recommended it's all dug out, a plastic DPM and a new screed. Anybody got over these issues without the dig out?

 

[gamma38]

Also my other concerns are that if there is such a product that can go over the slc i have no idea what slc was used and if it's suitable to be in constant contact with moisture.

 

[Flintstone]

Sounds like a get out of jail free card saying that, what's a dpm for ? To stop damp coming up ! Tilemaster do one, try calling there tech

 

[gamma38]

Sounds like a get out of jail free card saying that, what's a dpm for ? To stop damp coming up ! Tilemaster do one, try calling there tech

From what i've seen and read they are all pretty much the same. But i'll give them a try tomorrow. Cheers.

 

[Old Mod]

Best way I'd imagine Paul would be to remove the latex and use Ditra, and probably tape the joints. It'll allow the terracotta to breath, and as it's a vapour equalisation barrier, it should disperse the moisture away from the new floor.

But just to be devils advocate.....
Isomat do a waterproof membrane that can handle up to 7atm both positive and negative, so maybe that's also an option.

Justguess work on my part, but I'd say it was worth a call or two.

Thoughts Marek? @ISOMAT technical support

 

[gamma38]

Best way I'd imagine Paul would be to remove the latex and use Ditra, and probably tape the joints. It'll allow the terracotta to breath, and as it's a vapour equalisation barrier, it should disperse the moisture away from the new floor.

But just to be devils advocate.....
Isomat do a waterproof membrane that can handle up to 7atm both positive and negative, so maybe that's also an option.

Justguess work on my part, but I'd say it was worth a call or two.

Thoughts Marek? @ISOMAT technical support

Cheers Marc, I did wonder about Ditra. Would you use the standard or the one that's made to go external ?

 

[Old Mod]

Cheers Marc, I did wonder about Ditra. Would you use the standard or the one that's made to go external ?

If memory serves, Ditra 25 is fine.
Please call them tho Paul.

 

[gamma38]

If memory serves, Ditra 25 is fine.
Please call them tho Paul.

Cheers Marc.