# Moisture Resistant Drywall in bathroom



## jburchill (Oct 3, 2010)

There was a topic about this not too long ago, and I don't think he got his question answered, and I didn't want to hijack his topic.

I have my bathroom down to the studs and we are going redoing the bathroom. My question is, (same as other person) how much of the bathroom should I use the moisture resistant drywall? My thoughts are Ceiling, and around the shower/tub.

Or should I do the whole bathroom. Its pretty small bathroom.


Thanks


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## Bud Cline (Mar 12, 2006)

Do the whole thing. Moisture is moisture and moisture is everywhere in a bathroom.


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## Jessidog (Jun 21, 2011)

I would use cement or fiberglass based backer board wherever you have tile. In painted areas, I would use water-resistant drywall (green board) or possibly look into the newer mold resistant drywall products.

David


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## Bud Cline (Mar 12, 2006)

> I would use cement or *fiberglass based backer board* wherever you have tile.


Jessidog, that is the second thread I have seen where you have recommended Fiberglas (based) tile backer. Please tell me the name of this product or post a link to their website. I know of no such product. I could be learning something here.



Another question for you:


> I would use water-resistant drywall


1. I also have never seen "water-resistant drywall". Where do you buy that?

Or...
2. Is "water-resistant" and moisture-resistant the same thing to you?


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## Jessidog (Jun 21, 2011)

Bud Cline said:


> Jessidog, that is the second thread I have seen where you have recommended Fiberglas (based) tile backer. Please tell me the name of this product or post a link to their website. I know of no such product. I could be learning something here.
> 
> 
> 
> ...


Hi Bud,
As I noted in my previous comment, I was wrong about a fiberglass board. The board that I thought was fiberglass is actually a cement-based product. I have used the board that has a cement core and is covered in a fiberglass mesh (I think). More recently, I bought a backer board that appears to be a cement product. It is easier to work with and has an imprinted grid to help align the tiles. I'm not sure of the product name, but it is a nice product to work with.

As for water-resistant vs. moisture-resistant, I'm referring to the green board that has been around for decades and was routinely used as backing for tile in showers and tub areas.

I apologize for any confusion due to imprecise use of the terminology.

David


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## Bud Cline (Mar 12, 2006)

David most of us here with some experience try to provide the DIY'er with accurate information at all times. Even when they do get totally accurate information here some of them either don't understand or don't pay attention, or believe everything they read. Some of them read it here and the next thing you know they are giving someone else advice here and things mushroom out of control pretty quick.

I don't often recommend products by name unless I am sure the recommendation is proven-out by my own experince.

You have made some additional comments that I would like to revise for the benefit of those that are lurking here and taking everything said here straight to the bank.



> As I noted in my previous comment, I was wrong about a fiberglass board.


That was in a different thread, not here.



> I was wrong about a fiberglass board.


Yow I know...I was trying to be diplomatic which is unusual for me. There is no Fiberglas board product per say. However standard cement boards do contain Fiberglas threads or a Fiberglas mat but they are all embedded just under the surface of the cement product.



> The board that I thought was fiberglass is actually a cement-based product.


Correct, most of them are. not all of them but most of them.



> More recently, I bought a backer board that appears to be a cement product. It is easier to work with and has an imprinted grid to help align the tiles. I'm not sure of the product name, but it is a nice product to work with.


That product is a fiber-cement board containing mineral fibers not Fiberglas. It is called Hardibacker and only the 1/4" version has the grid lines stamped into it.

The grid is not really to help align the tiles as the quality control on the grid placement is very poor. The grid is more used to help with the fasteners, in fact the board is also dimpled where the fasteners should go under most circumstances but not all.



> As for water-resistant vs. moisture-resistant, I'm referring to the green board that has been around for decades and was routinely used as backing for tile in showers and tub areas.


There is not really a water resistant board in the drywall class. Those are "moisture" resistant meaning a little moisture won't hurt them all that much. Let them sit in water directly and the story changes radically.

Moisture resistant drywall is not for showers and tub areas. That is what cement backerboards are for. This isn't to say moisture resistant drywall isn't used in showers and tub surrounds but it should not be. Ever. There is only one application where drywall is allowable in wet conditions and that is when it is clad with a vinyl covering made exclusively for the purpose. Noble CIS and Schluer KERDI Mat are two of those products. There are others.



> I apologize for any confusion due to imprecise use of the terminology.


No apology necessary but in the case of showers and tubs accuracy is everything.


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## Blondesense (Sep 23, 2008)

jburchill said:


> My question is, (same as other person) how much of the bathroom should I use the moisture resistant drywall? My thoughts are Ceiling, and *around the shower/tub.*


Just to clarify, but what precisely do you mean by "around the tub/shower"?

I assume Bud interpreted this as outside of the enclosure. If you mean inside of the shower however, then no. No drywall products of any kind in a wet area unless they are protected by Kerdi.


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## Bud Cline (Mar 12, 2006)

*Good catch Blondesense!* Thanks. I screwed that up a little. I was thinking all of the walls OTHER THAN THE SHOWERS but that's not what I conveyed.


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## Jessidog (Jun 21, 2011)

Bud Cline said:


> David most of us here with some experience try to provide the DIY'er with accurate information at all times. Even when they do get totally accurate information here some of them either don't understand or don't pay attention, or believe everything they read. Some of them read it here and the next thing you know they are giving someone else advice here and things mushroom out of control pretty quick.
> 
> I don't often recommend products by name unless I am sure the recommendation is proven-out by my own experince.
> 
> ...


Thank you for your comments and clarification on the various products. I learned a lot.

David


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## jburchill (Oct 3, 2010)

Blondesense said:


> Just to clarify, but what precisely do you mean by "around the tub/shower"?
> 
> I assume Bud interpreted this as outside of the enclosure. If you mean inside of the shower however, then no. No drywall products of any kind in a wet area unless they are protected by Kerdi.


What I meant by around the tub/shower area, is from the top of the shower/tub which would be around 76 inches for the one I was looking at. so From the top of that to the ceiling, and including the ceiling. That was the area i was questioning the use of greenboard (moisture resistant drywall).


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## Gary in WA (Mar 11, 2009)

The 2009 IRC for most of the U.S. specifies ½” water-resistant board on framing maximum 12” on center (ceilings), 5/8 is OK- 16"o.c.: http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_7_sec002_par014.htm

No Class 1 (poly) or Class 2 (paper-faced fiberglass batts) under the w-r board: http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_7_sec002_par013.htm

Guide for fastening regular drywall and applications: http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_7_sec002_par010.htm

http://www.usg.com/rc/data-submitta...um-panels-water-resistant-submittal-WB634.pdf

Gary


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