Nope, i was a trained chem engineer. But career cut short to take over dad stuff coz he was sick. But i like DIY stuff, I renovated whole condo myself, not a lick of contractor step into my house.
Very nice space. But i would keep the roof as light traffic as possible. coz flat roof a lot of headache
I actually have one space to utilize this idea. but i scrap it because it'll sure need a proper column and beam to build vertically. The calculation, the material, building it will also be difficult.
Im calculating the footing now, later the structure. then only can estimate how much the cost.
This is what i worry most. Are you an architect? how flat was your roof? let say if i pump the slope up to 1:15, coat with a cementitious waterproofing (ppl use this to coat their large fishtank), finish with elastomeric waterproofing, will it work? can you explain more about your previous experience?