Replacing a portion of a ceiling

Something fell in my attic and damaged a section of ceiling ~6'x6'. I plan to remove an area 8x8' and replace it.

My perceived problem is that the current ceiling is 3/8 drywall over 3/8" drywall. I plan to replace with two layers of 3/8" drywall. I also plan to buddy the existing joints with 2x4s so that I have more surface area for nailing.

How do I resect the existing drywall? I have total ceiling access so I could cut from above.

Yes, I've thought about a textured ceiling. Per the wife "There are two types of people: people who like textured ceilings and people with taste."

This represents ~20% of the area in the room, so I don't want to redo the whole thing if I don't have to...

Any ideas?

 

I'm not 100% following your concerns. Cut the old drywall back to the nearest rafter. Then add a 2x4 to the side of the rafter to attach the new drywall. Tape, sand, paint, done. Areas where the rafters run perpendicular to the opening should not need anything extra for framing.

Not sure why they used two layers of 3/8 drywall. I would think it would sag over time.

 

I've worked on a few homes where they double laminated the drywall but never seen 3/8" used on a ceiling. Like TI, I'd enlarge the hole to the nearest rafters, add 2xs at the right height and install one piece of 1/2" or 5/8" Assuming it's a slick finish ceiling, basically you just tape float the mud out further each coat until you get it even. While the repair should only cover a small portion of the ceiling it is likely you'll need to paint the whole ceiling. Ceiling paint doesn't touch up well unless the paint job is fairly recent.

 

And use drywall screws not nails!

 

I appreciate the advise on placing the 2x4s inside the existing rafters... and the use of 5/8" drywall.

 

Cut drywall with a utility knife (Razor knife). Score on one side, bend the sheet and the sheet will snap on the line. Finish by cutting the paper on the back side. No dust, no (almost) mess. CUTTING DRYWALL PART 1 (CC) - YouTube

Place the 2x4 so that the bottom of the board is flush with the existing rafter. Fasten with nails or screws. This should only be need where the rafters are parallel with the opening.

 

I think I would cut short pieces of plywood 5" wide to fit between the joists on the two sides that run perpendicular to the joists. Screw them so they are half on the od rock and half sticking into the open space 2 1/2" This will tie the edges together on those sides. The 5/8 doesn't need it so bad but it will help the two 3/8" layers keep from further sagging when supported a bit by the 5/8"

 

I am familiar with cutting new drywall for installation. I am interested in whether there is a less mess way to demolish the existing ceiling.

 

I figure there is a lot more mess in the insulation than the drywall. cover cover cover, seAl up the room and take the stuff out a window if you can, maybe, just maybe you can do it without messing up the whole house.
Oh, I see you have good ceiling access. Move all the insulation you can before you cut. Just scoop it well away from where you intend to make the cut.