Wrong self leveling compound? - Tile Advice

[s wilks]

We are currently laying electric underfloor heating in our kitchen in an area 7 sq m. We have laid 10mm insulation boards then the heating mat.

Browsed on here & discovered that self leveling seemed to be the best way to go so went and got some unibond self leveling compound. After laying it was reading a few more posts & see that it should be a flexible slc. :mad2:The unibond slc doesn't mention flexible on the bag. Have rung them & a chap in the technical department said that the formula for the slc is fairly similar to the flexi adhesive so might be ok. He said it will be tested for ufh compatability in the future.

What should we do now? Rip it all up & start from scratch or take a chance & lay the tiles (porcelain 600mm sq), wait a few weeks turn it on & hope for best.
Has anyone had any experience with this product?
Thanks in advance for any advice.

 

[diamondtiling]

:welcome::welcome::welcome:

I think the answer from Unibond tech was a little lame to say the least, You should have used flexible slc for sure, its going to heat up and crack the slc you have laid and that will lead to problems with the tiles, how long has it been down?

 

[s wilks]

Thanks for the quick reply. The slc has been down since yesterday evening.

 

[diamondtiling]

Hi,
sorry i should have read your top line regarding the insulation boards, you are not going to get the slc up without damaging the boards, does it mention suitable for ufh on the bag even if it does not say the word flexible?

 

[s wilks]

No, but it doesn't say it's not suitable:smilewinkgrin:. It does say not suitable for external use, or onto bitumen tiled or wooden floors.

 

[diamondtiling]

I really have no idea what to offer you by way of help, I have never been in that situation so I think it best to wait for further replies, there are specialists for your type of problem that will be on later and am sure they will help

 

[s wilks]

Ok, thanks for your help.

 

[bert&ernie]

They best way forward might be an uncoupling membrane ontop of the slc incase the SLC does start to crack.
Make sure you use the right membrane and that it does not act as an insulation layer and therefore slow the heat transfer from the UFH though to the tiles.

 

[kilty55]

my advice would be to start afresh,,you may well lose your u/floor heating and ins boards but if you tile it and it does crack youll be more upset,what an expense that will be.

if non flexi slc was suitable we would have no need for flexible

i understand the situ your in but i strongly feel you will regret it in the long term if you tile it/

 

[DHTiling]

Un-coupling membrane will be the best way....then if the slc does crack it will not affect the tiled installation...

 

[kilty55]

what if the slc cracks then over time starts to break up,,effectively the membrane wont be stuck to anything apart from a broken floor which surely would affect the tiles?

 

[DHTiling]

No problem.....the tiles are stuck to the membrane ... i,e ditra/durbase....the fleece is stuck to the slc so if it seperates then no prob as the tiles are stuck to the top coat...sort of like a floating floor but with no deflection issues...

It is just a solution and not a remedy for all jobs but will work...wetdecs also mentioned this method ages ago..

Different story if it was a timber floor.

 

[kilty55]

cool,you learn something every day on ere

 

[faithhealer]

cool,you learn something every day on ere

thats why we keep logging on eh kilty