Decoupling or not.....

[inspiredandy]

Evening all.
I am in negotiation with a client over a tiling job. 33sqm tumbled marble over two substrates on a kitchen floor. One side floor boards one side concrete, I have priced to over board timber and pour levelling compound on the concrete to make the levels up. I have also priced to install decoupling membrane over the whole floor but wonder if its a bit over kill. My price is about xxxx (no prices in the open forum) a drift but client wants me to carry out the install. Thoughts appreciated...

 

[Just Rizzle]

what are u over boarding timber floor with ply or hardy or other?

 

[p4ulo]

Make sure you put a movement strip between the two different floors too, and deffo decoupling for absolute piece of mind, espec with natural stone.

 

[inspiredandy]

Over boarding will be done with 6mm backer (probably hardie) glued and screwed.

 

[inspiredandy]

that was my thinking @p4ulo

 

[AliGage]

Decoupler and expansion joint is a must IMO

 

[Lee@emctiles]

Decoupler and expansion joint is a must IMO

and mine.......but then the client will say they dont want an expansion strip in the middle of there tumbled marble floor!

 

[On one]

and mine.......but then the client will say they dont want an expansion strip in the middle of there tumbled marble floor!

But then custom made colour coordinating expansion joints are available to mitigate this problem. Available at short notice and to match any coloured grout you care to mention.
Not ideal.....but the other option is going back in a number of months to replace a hairline crack right across the floor

 

[widler]

Why would you need a decoupler ?
Is there ufh ?
Id put a movement joint in, work from where the 2 meet, and silicone instead of grout

 

[Dan]

Just the fact it's tumbled marble I think mate. Which is quite weak.

Personally I'd trust the adhesive and not bother.

 

[widler]

Would think it would be overkill , as long as the floor (timber) is solid it will be fine without.
IMO

 

[Old Mod]

Would think it would be overkill , as long as the floor (timber) is solid it will be fine without.
IMO

See now I'd go the other way Craig!
I'd stick Ditra to the ply with AF200 rather than over board, as long as the sub floor is solid.
If it isn't then I'd overboard as well.
Couldn't imagine putting down such a delicate material without Ditra.
And obviously putting expansion in Ditra too!

 

[AliGage]

Can't think of a time I've ever fixed stone to any floor without using a decoupler tbh