What type of sandpaper should I use?

Ooh, bulb will love this question :)

Google

when you say “rough and bumpy”, how bad do you mean? you may need to do a skim coat w. joint compound first

Go to a hardware store, and get a pole sander and sanding screen, if it is a large area. For smaller imperfections, you could try 80 – 120 grit sandpaper or a sanding block. The higher the number, the finer the grit. I hope this helped. Good luck!
P.S. I don’t think I would do the skim coat of joint compound, unless it’s a small area, because that would entail more sanding. Joint compound is to fill joints, as the name implies.
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Bulb’s a carpenter :)

He knows! :D

what makes you think this bulb guy is the only carpenter on this site? Squirbel- I think you need to get of his tip.

I never said he was the only one. I know he is one, and don’t know anyone else is. He’s a friend, and you are rude.

I would use a 60 grit sandpaper if the surface is really rough