Here is an example of some outdoor furniture on a private patio.

Your best bet is to have a residential structural engineer do a site visit and a soil test. As the home is only 10 years old, it is normal to have some settlement and additional settlement after 10 years should be minor. The fact you are concerned of future settlement should be a red flag. Additionally, you are concerned about moisture. Two red flags. It is your choice, but buyer beware. Best of luck.

5th floor...maybe a hobby room. E.g. stargazing with telescope. Ideal if the 5th floor in building contained a patio...no roof...the patio is the roof for the lower stories.

Hi drmdilip -- While I waited for my trumpet vines to fill in sufficiently to provide summer shade, I sewed three matching striped shower curtains together, using the button holes on each end to tie it in place. I did this because as the vine was growing new, each thin runner would drop between the rafters rather than grow straight across. After a few years now, those thin runners have become a massed layer of thick vines, all of the new growth is straight up and by the end of summer I'll be able to easily remove my temporary support and have a roof of vines. It's not rainproof though -- for that, polycarb is practical, and I love the copper above!