Wall and flooring widths?

I am currently trying to design the interia of my extension plans and was wondering, how thick would a 2 story exteria wall be including internal studs & plaster? I realise there's probably a dozen or so answers but lets say most common construction of a cement block 2 story wall. Also how thick would the 2nd story floor be? reason I ask is that I plan to put in an upstairs bathroom and figure it might need to be thicker in that area or maybe just along the wall below to accodate pipes....

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