Polished concrete for new slab

[pokop]

Hi all, I’m doing an extension that will have a polished concrete slab in the new section. I have had a builder tell me that the best practice is to have a ‘normal’ structural slab then pour a thin ‘finish slab’ after the walls/ roof is up and cut and polish that polished concrete Atlanta. Does anyone have any advice regarding the relative benefit of doing it this way as opposed to simply cutting and polishing the structural slab?