Drywall Thickness for the Ceiling

[Beltzington]

As always I appreciate your feedback, a lot of good ideas, I wish I had considered using 1x3" strapping earlier in the project it would have resolved a couple issues. I tore everything down to the framing as I moved one wall and added another and I agree dealing with the old blown-in insulation was no fun.

I already have installed blocking, electrical, vents and insulation so not going to tear any of that back-out to add framing, fortunately I found a local lumber-yard that sells XP Purple drywall which is both moisture and mold resistant but not called green board. Additionally they have 10' long 5/8" sheets which will allow me to span the ceiling without any butt-joints and 1/2" 8-foot sheets for the walls. Now the easy part, hanging a 10' 5/8" board by myself

Thanks again and Happy Holidays!

PS what is the purpose of a vapor barrier on the ceiling, the attic is well ventilated and other than some moisture damage I found from leaking vent caps I saw no problems above the bathroom and it is a ~20-year old house.

 

[GLyford]

buy or rent one of these:

Drywall Panel Hoist / Lift

I did a kitchen and porch and my brother in law did his bath, both had some sloping ceilings. A little clunky, but they do a pretty good job, nicest thing is it holds the sheet while you get some screws in.

 

[Cord]

PS what is the purpose of a vapor barrier on the ceiling, the attic is well ventilated and other than some moisture damage I found from leaking vent caps I saw no problems above the bathroom and it is a ~20-year old house.

At different times of the year there will be a vapor drive through the wall assembly that will result in condensation in the insulation. The purpose of the vapor barrier is to stop this drive and help keep the insulation dry. The vapor barrier always goes on the warm side of the assembly. For me, it's on the inside face of the wall. In warm climates which are primarily cooling, it's on the outside face. I see that you are in Georgia so I'm not sure where the warm side is in your wall assembly. There are a few localities which have no vapor barrier because they waver between heating and cooling. To help you out, I attached the code and a link to the climate zone chart. I'd still recommend checking your local code because it could be different.

https://www.energy.gov/sites/prod/files/2015/10/f27/ba_climate_region_guide_7.3.pdf

 

[Steppenwolfe]

Still trudging along with my master bath redo, I am about ready to hang drywall and was planning on using water resistant green-board on both the ceiling and walls. Unfortunately no one locally carries 5/8" thick green-board. This leaves me two options, go with 1/2" green board on the ceiling or standard 5/8" drywall on the ceiling.

Ceiling joists are 24" OC and code does not require type x fire proof drywall however from research I am concerned 1/2" may be on the marginal support side especially with a textured ceiling. Specs for 1/2" green board say it is approve for 24" OC as long as it is perpendicular to the rafters which it is.

Should I be more concerned with moisture damage or drywall sagging?

L&W supply in Evans will have 5/8 green or purple board.