Exterior Drywall Sheathing?

Popeye42

I have started doing a renovation on our master bathroom. After the demolition, I noticed that the exterior wall had what appeared to be drywall as the sheathing. Problem is that the drywall did not go all the way to the top of the interior wall, so the top of the wall was open to the outside air. Looks like we also obviosly had some rodent or larger, probably a raccoon or a opposum trying to eat its way into our house.



I would like to seal the exterior wall all the way to the top of the interior wall and add insulation to this area as well. The space between the stone facade and the sheathing appears to be filled with blown in insulation. How should I go about adding the additional drywall material to seal off air penetration into the bathroom? I should be able to get some access through the soffit but not sure how much.

We live in west central Georgia, and I have never been able to get a good handle on whether to have a vapor barrior or not, or for that matter where it should go. I would like to add insulation between the exterior drywall and interior drywall, but do I need to add a vapor barrier as well?

Would that be creating 2 vapor barriers (exterior drywall and kraft faced insulation)?

Any help you can give would be greatly appreciated.

Gary in WA

You will see your location better than I; http://www.buildingscience.com/docum...ecommendations

No v.b., correct? Add some plywood to close off the top framing. Add some foam board over the wall plates if tight on room; http://www.homeenergy.org/archive/he...96/961110.html

Unfaced insulation if in Zone 4. The gyp-rock on the exterior is exterior application drywall, or similar. I don't believe the facing on it is a vapor barrier as it is paper, if I remember correctly. Installed it 30 years ago....

http://www.energysavers.gov/your_hom.../mytopic=11810

Gary

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Popeye42

Gary,

Thanks for the reply. But unfortunately still confused.
Your first link appears to say that a vapor retarder is not used where we live, Zone 3a (right about at the white line). It says to avoid one on the interior in these Zones, but it does not spcifically say not to have one with it oriented to the outside. However, your last link would put us just barely in the interior side vapor retarder zone. Maybe there is not a clear distinction for this zone.

So basically, I just need to block off the area above the gyp-rock to the top of the wall. Should I spray foam (can type) the area to block off any air penetration?

I then want to add fiberglass batt insulation between the exterior gyp-rock and the interior drywall. At this point, I am guessing that would be unfaced insulation?

Thanks.

Gary in WA

You can use some house wrap tape to seal the joints. Here is a link to your State Energy Code, it will tell you if a vapor retarder or barrier is needed; http://www.archive.org/details/gov.ga.energy

Read this on the "biggest loser" in insulation that I put together to get the most for your money; http://www.diychatroom.com/f98/how-b...ulation-90438/

Gary

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