Ufh xps panels can they sit on kingspan??

[Northern monkey]

Good morning, I may have made a faux pas, we are having a new extension with new floor - we have the new concrete base 125mm lower than existing floor level - need 100mm kingspan for floor insulation and the master plan was to use low profile xps grooved panels for the ufh then tile on top.

 

now you’ve all ready probably identified my problem, a) can I adhere the xps panels to the kingspan directly? And b) will it be strong enough? Or have I proper stuffed up and need to board over the kingspan first?

 

thanks

[Northern monkey]

To clarify I was hoping to use 18mm grooved cement boards 

[Russell griffiths]

I may be wrong, but are those grooved panels not a retro fit solution and designed to go over an already solid floor, and then you lay your second floor on top. 

How is your design going to be level or flat?

will the xps panels not move about unless fully bonded to an underlying structure. 

Do you have a link to the product. 

[andyscotland]

Don't know for sure, but certainly when I spoke to ProWarm tech support last year about their 18mm dry screed boards they said I'd need a floating chipboard floor between the insulation and the panel, as the insulation alone wouldn't be firm enough.

[PeterW]

2 hours ago, Northern monkey said:

To clarify I was hoping to use 18mm grooved cement boards 

 

Those are like the Fermacell boards and I think can be laid direct on insulation. Have you got the product name ..?

[Northern monkey]

https://www.thefloorheatingwarehouse.co.uk/acatalog/Grooved-Cement-Boards.html

[Northern monkey]

My considered options are a chipboard base on top of the kingspan then the ufh boards but that would raise my overall floor by 15mm

or placing battons on the concrete floor - kingspan between then use the cement boards on top which should keep the level 

 

 

[Temp]

I would ask them if the cement boards can be laid direct on joists and tiled. I doubt they will say yes but if they do then laying on battens should work. 

 

The problem is tiles need a quite rigid floor. Any flex when teenagers dance on them will cause trouble.

[PeterW]

I’d contact Cellecta directly who manufacture them and see what they suggest. 

 

Alternatively you can look at Fermacell who do allow the use of their boards direct onto rigid insulation however you need two layers of 12.5mm, or alternatively one of 12.5m and one of their overlay boards with a staggered joint pattern. 

 

That would mean you need to drop your Insulation level to 95mm but this seems a very expensive floor build up whichever way you look at it ... 

 

 

[Temp]

18 minutes ago, Northern monkey said:

https://www.thefloorheatingwarehouse.co.uk/acatalog/Grooved-Cement-Boards.html

 

I accidentally "liked" this post above.

 

I'm not keen/convinced about their "turning boards" that seem to need a thin layer of levelling compound. Would they be as strong/stiff as the cement boards?