I’m rehabing a finished basement that has had mold problems. This includes a new fiberglass shower which requires new sheetrock around it and on the ceiling.
Not sure what is a better sheetrock product to use: the old standard ‘green board’ or this newer DensArmor ‘paperless’ sheetrock (Georgia Pacific).
Any comments when one is better than the other?
Thanks,
Jim
Listeners write in about fireplaces affecting family harmony and bionic suits, before asking questions about brick steps, ground-source heat pumps, and building a dome greenhouse in Maritime Canada.
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial NowGet instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
Replies
I'm doing a bathroom right now. I'm putting in the DensArmor. On a small bath, the extra dollars just are not that much.
It is true that I don't really know how good or bad the DensArmor is, but I do already know that green board is only a marginal improvement over ordinary drywall, so....
Rich Beckman
View Image
Thanks Rich. I though reading that 'green board' is no longer approved for use in bathrooms, etc. but cannot find that information again. The paperless drywall seems like it is worth a try.
Jim
20ph,
You are reducing the "food-source" with paperless drywall...what about the moisture source?
Are you taking any steps to reduce moisture?
John B
Hello John,
Yes but my options are limited.
Thanks,
Jim
Why not just user hardybacker or densheild throughout the whole bath if you are so worried? And it is not true that greenboard is no longer approved for bathrooms, but rather it is no longer approved be the TCA for use under tile on bathroom walls.
Either way i think putting up a vapor barrier is going to be the best thing to do.When in doubt, get a bigger hammer!
To be specific, greenboard is no longer approved as a tile backer in wet areas (showers, etc). This is the tile industry's standards group, not code per se, but some codes refer to it.
If your view never changes you're following the wrong leader
Dan, I'm fairly certain that IRC prohibited it as well with the January 06 revision.Lemme see if i can find a reference...
Here's the quickest cut and paste reference that I could find:
Section R702.4.2 that “Cement, fiber-cement or glass mat
gypsum backers in compliance with ASTM C1288, C1325
or C1178 and installed in accordance with manufacturers’
recommendations shall be used as backers for wall tile in
tub and shower areas and wall panels in shower areas.”
There are a few other caveats in there, but it all depends on if the Jan 2006 revision has been adopted by the local agency.
But as far a good building practices, it's either cement board or fiber cement, which both require a barrier (like 6-mil poly) behind them or Kerdi over them, or a glass-mat product like Denshield, which does not need a barrier behind it but needs proper detailing to cut edges and fastener holes.
This refers to tile backer in wet areas, like showers or tub surrounds.
Wanted to add one more thing:In my area, per code we can't do Kerdi over drywall. But with documentation certificates from Schluter the inspector says we can, but it's on a case-by-case basis.Most guys here know that TCNA isn't code, it's more suited to the "best building practices" category. TCNA is a more flexible agency and it's easier to change than code, so it's usually more timely than code and some local agencies use TCNA guidlines to supplement the national code. It seems to take a cycle or two before TCNA recommendations are incorporated into national code.
DensArmor is all I would use. I do not even touch greenboard any longer
Durock or other brand cementboard. Excellent product for kitchens, bathrooms etc. I would never put drywall in a bathroom, no matter what colour skin it has.
Simon
Are you referring to the "wet" areas like a shower or do you mean anywhere in the entire bathroom?
I think greenboard works well in bathrooms, but obviously not as a tile backer. I haven't used the paperless drywall yet.
Entire bathroom. I am in the middle of redoing the kitchen and I used it everywhere but the ceiling.
Simon
Wow! I never heard of anyone doing that before. I think it's overkill, but it's also pretty good insurance against moisture problems.
Not to mention heat. I believe it can be used to reduce wall clearances for woodstoves in some locals as well.
Simon
USG has actually stopped making what most of us are used to calling "green board", which is called ToughRock MR (the MR stands for Moisture Resistant). They have *supposedly replaced it with another product, which is the exact same shade of green, which is called Mold Tough. (Note: I think they also eliminated Humitek and the other drywall used for wet locations as well...not sure of all the names)
Mold Tough has a perfect score on the ASTM standard for resisting the growth of mold; I believe both the paper and the core are treated. National Gypsum also has a product that has an equal score, it's purple instead of green.
I doubt that either are approved for use under tile in bathrooms - they are designed for "incidental moisture" like splashing water, etc.
* I say "supposedly replaced" because this was transition to the new product happened months and months ago, but my local home depot still has the old stock.
Justin Fink - FHB Editorial
All of these drywall choices can be a little confusing. Maybe it's time for a FHB article on choosing drywall, something a little more than "what's the difference".
At the local big box, they stopped carrying DensArmor (paperless drywall) probably because it didn't sell very well. I have a feeling that the product may have been developed as an over-reaction to the fear of mold.
You make a good point, and we're on the same page. It's something we might play with in the future.Justin Fink - FHB Editorial
We're getting purple drywall at the lumber yard. I haven't even looked to see who is making it or spec's.
Mold and moisture resistant we are being told.
Dens Armor special order only at the Lumber Yard.[email protected]
That's the National Gypsum XP. I just hung about 100 sheets of it this winter - works just like regular drywall, none of the fiberglass.Justin Fink - FHB Editorial
Large bathroom?
Ah, basement...........[email protected]
Besides the board choice, you have a choice in terms of the taping compound. If you can, stick to the 'hot' muds. They won't react with the moisture in the bathroom once they have set up.
I used DensShield (I think it was). Watch out for texture, which is good for tiling but bad for painting. In particular, it will be smooth where you tape it.
DensArmor will need to be skim coated and you need to adjust your screw guns to barely dimple the skin.
We use the "new" 5/8" green board cielings and skim everything that's not tiled.
The awful thing is that beauty is mysterious as well as terrible. God and the devil are fighting there, and the battlefield is the heart of man.
- Fyodor Dostoyevski
I know you couldn't use the old green board on ceilings... is it the same for these new boards?
I think that's changed - though probably still a concern if your spacing is 24 on center.Justin Fink - FHB Editorial