I just did mine today in my 30x40x12 high, pole barn.. 8Inch Double wall stainless thru the ceiling and roof. $100 each 3 foot section. below the ceiling, standard 8inch black stove pipe.
Down to a T. elbow off of it,(gives me a clean out) at 6 foot level, then down to stove.
I used a ceiling support that will hold up to 50' of pipe. Attic insulation guard. etc.. all up to code for everything.. Took me a couple hours to cut the roof hole, Build frames there and in the ceiling, put up the ceiling support and assemble it all...
Bob