Basically, I’d like hear any experience with using drywall for an “exterior” porch ceiling. The one I’ll be doing soon is technically an exterior porch, but it is fully enclosed with jalousy windows and has a large overhang. It never sees rain/snow, but the humidity levels will reach about the same as outside.
If it will last 5 – 10 years, I’d like to use regular drywall… I’m familiar with it, it’s readily available, it’s reasonably priced and it weighs considerably less than exterior drywall (50 lbs vs 70 lbs)
National Gypsum sells exterior soffit board and USG (Sheetrock) sells what they call FIBEROCK¯ brand AQUA-TOUGHâ„¢ sheathing which is basically the same thing, but it only comes with square edges. These would probably be the ideal products to use, but I’m wondering if they’re really necessary for this porch.
-Don
Replies
Don,
As a practical question, there's no reason that standard sheetrock cannot be used in the manner you've described. I've used it in just such a place, where it even suffered a leaky roof for a few days without ill effect.
Check into paperless drywall. I don't know, but it may be more resistant to mildew, which is a possibility in an enclosed porch. Mildew likes paper.
Two years ago I was hired to rip down a drywall ceiling from a porch. I insalled PVC beadboard in its place. The reason why it had to come down was not that the drywall was failing, but because the tape and joint compound were dropping off in ribbons. They must have used either regular mud or maybe the easy sand stuff. This was on a beach house, so moisture levels were elevated most of the year.
So, if you really need to install the stuff on the porch, you might have better success using Durabond setting compound. Though I've never tried to to find out.
My .02, fwiw.
"I am the master of my fate, I am the captain of my soul." Invictus, by Henley.
Why not use stucco? We have a few places with STO and have great results and life span.
I worked on a similar project about five years ago -- more like a sun room, though. Space is not heated.
We used sheetrock for the ceiling, but instead of taping the joints, we used natural finish birch latice which I made, and installed it in a geometric design that also covered all the joints.
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"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Thanks for the replies. Let's see if I can respond to a few of you in one post:
Mark, I like the idea of the paperless drywall (such as DensArmor), but the stuff is so flexible that I'm afraid I would get sagging on this ceiling. The joist spacing is 19.2" (black diamonds). I'm comfortable stretching regular drywall the extra 3", but not this paperless wiggly stuff.
Nick, Thanks for suggesting Durabond. I've used it and I like it. It's not really water-proof, but it's definitely more moisture-resistant than regular compound. Of course, I'll still need to topcoat with something else since Durabond is really hard to sand. (And yes, I still sand my spackle jobs, if only a little).
Rob, Stucco would probably be the perfect material. Unfortunately, I have zero competence with it and I'd rather not start with a ceiling.
-Don