I am finishing a basement and had planned on drop ceiling, but now I
am considering smooth if I can either frame out the ceiling myself or
have someone do it for a reasonable cost.

I have a 9ft ceiling, and need to frame out at around 7.5-8ft to get
below the ductworks/pipes etc. Some of it will be tray in the larger
rooms.

I framed the walls in my basement, so I am assuming doing the ceiling
is similar? But since it is over your head, there are probably
special considerations.

Any guides or photos on how to frame this out? I tried to google but
did not have a lot of luck.

1) general code requirements?
2) size of boards, 2x4?
3) any maximum lengths or spacing between spans (ie can you span a
16ft board across the room or should it be 8ft nailed to support then
run another 8ft)?
4) how to hang/secure to joists?
5) can boards be nailed on ends or should I use hangers?

Framing a wall was not that difficult but a ceiling is pretty
important to get it right. Thanks for any help.