Drain in Central Air

When new greenboard is installed in the bathroom what steps should be taken to paint it. Is there special preparation?

Hello all, I am smack dab in the middle of a bathroom remodel and, having finished the rough-in of the plumbing, electrical and framing - now need to install the bath fan and vent (among LOTS of other things - whew!). Fortunately, the bath is upstairs and directly above it is unused attic space, which makes for easy work above. Unfortunately, there are no soffits in my 75-yr old house and the closest end of the gabled roof is 20' away, so I'm guessing I should just go straight up out the roof (which will only be about 2-3 feet long) with the exhaust vent. We have a single layer of asphalt shingles. Although I fancy myself as fairly adept at new remodeling projects, cutting a hole in my roof is a bit worrisome for a non-professional like me (absent this forum's wonderful advice, that is). I've got my nice Broan fan and am ready to install the exhaust vent out the roof, but am looking for some guidance on how to go about the process. Where do I start and what pitfalls do I need to be aware of as I undertake this. Look forward to your comments. Thanks in advance, Mark in KC