External concrete slab for 20mm porcelaine

[Italy]

Okay, Im erring on the adjustable pedastel system rather than porcelquick as it doesn't involve cement and adhesive. However, to create the inside & outside seamless look I would need to grout externally. I assume I do as otherwise the external tiles without grout would look like an unfinished job when compared to the same tiles internally with grout, unless anyone else would disagree.

I assume you can use the grout backing rod with the adped sysem too as with the porcelquick system??

I don't know the systems you mentioned,
here in Italy I saw them all without the grouting