So I decided to drop a quick email to Wundafloor technical regarding the application, crossing substrates and the need for expansion gaps, below is the response I got -
Our first consideration is the transition between the concrete/floorboards section. We would hope to see it flat, stable and level.
Secondly, regardless of tile dimension the adhesive being used is highly deformable thus taking movement & expansion into account, either C2 E S2 or C2 FT S2. This has always been sufficient in the case of large format tiles over large areas and we are unaware of any further expansion gaps being necessary.
We’d advise consulting with your tiler on this matter, as they may wish to recommend further decoupling/anti-fracture strategies etc. As far as we’re concerned though, we’re quite happy to see tiles of those dimension bonded directly to the panel using a highly deformable C2 E/FT S2 adhesive.
Considering what I have read on this forum, I would be surprised if they were unaware of any issues!
Not sure if the above is useful, but thought I would share it with you all anyway.
Catch 22, don't follow their instructions and there is no arguement from my side, follow their instructions and it goes wrong and it becomes he said she said and trying to prove it was done right. Seems like I am damned if I do or damned if I dont...
Once again, thank you for all of your assistance with this.
Cheers,
Nic