Perimeter gap / expansion joint size?

[WillCalderwood]

Hi all.

I've had a bit of a trawl through the forum and can't seem to find any numbers as such. We're laying about 27m2 of Travertine over wet UFH, going down on Durabase matting. We're wondering how much of an expansion gap to leave between the base of the external door and the tile? And I assume we should leave a similar amount around the perimeter of the entire room under the skirtings?

Also, at the base of the door we have 25mm Celotex + edge expansion foam, so there's ~30mm where the decoupling membrane is not attached to a solid substrate underneath. I'm guessing this may be a consideration in the side of the gap?

Thanks

 

[Ajax123]

Expansion joints should be between 5 and 12mm

perimeter edge should be 10mm