Travertine Floor Tiles Substrate Preparation - Advice Needed Please

[cr0ft]

Hi all,

I've been asked to tile a Travertine floor which has been prepared as follows by the customer: -

1.) All floorboards removed and replaced (20mm floorboards).
2.) 12mm WBP laid across the floor from wall to wall. Screwed at centre in both directions from 150mm - 250mm (varying across the floor).

The floor feels fine and there is no detectable up and down deflection in the floor. They have asked me whether a decoupling membrane should be used on this floor. I'd appreciate some advice from a tiler with more experience than me on this one. They are willing to pay for a decoupling membrane if needed but with adhesive it will cost them around £300 for the whole room plus my labour to install it.

I've asked them to screw the floor at 100mm centres in both directions as I believe this will stop any lateral movement. Is the decoupling membrane really necessary in this case? The floor is around 5m in length by around 3m.

I'ld appreciate any quick answers as I'm starting the job on Wed and want to advise the customers properly.

Many thanks!

[tommyzooom]

Can you clarify, The floorboards have been removed and 12mm ply has been fixed directly to the joists?????

[whitebeam]

As it is Travertine I would, it's a soft stone and can crack easily with expansion

[david campbell]

i would use one also,but not with you on lifting the floor boards? have you replaced old with new or replaced with ply?

[timeless john]

I think I read it :
New 20mm floorboards.
Then 12mm WBP plywood screwed at 150-250mm centres.
As Whitebeam with Travertine worth the extra by using a decoupling membrane.

[cr0ft]

Thanks for all of the replies. They have replaced all the old rotting floorboards with new ones then overboarded the floorboards with 12mm ply. I've just asked him to put screws in every 100mm in both directions to reduce lateral movement.

I'll tell them to go with the membrane, I know wooden substrates can cause problems if the job isn't done correctly and I want it done properly for them.

Thanks for all the advice, it's sometimes a bit confusing about what preparation is required for which tiles and it's good to have a forum like this to get advice on.