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Green Board or Not???

Posted by fqp25 (My Page) on
Sat, Sep 2, 06 at 10:54

I have a question about "Green Board" for bathrooms. I have always used this for moisture protection. Now a drywall contractor has told me that "everybody" has stopped using it. For what reason I have have no idea.

Does anybody know the reason? Or is he just trying to save a Buck? This falls into a moisture control question. I don't mind somebody trying to save a buck, but as long as it doesn't cost me in the long run.

I would love to hear your opinon, Thanks.


Follow-Up Postings:

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RE: Green Board or Not???

Green board does not work.
It is not adequate for tile backing, and has no real advantages over plain old drywall, a coat of primer, and two coats of paint.
There are also rules limiting its use in ceilngs cause it sags so bad. In many cases you would need ceiling joists on 12 inch centers to use the stuff.


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RE: Green Board or Not???

My hubby is a builder I asked him he said no they now use cement board instead.For baths etc


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RE: Green Board or Not???

Cement board is used as a tile backer.
Green board was never intended to hold tile, despite a lot of cheap builders trying to get away with it.
For non-tiled walls in a bathroom regular drywall is fine.


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RE: Green Board or Not???

Around here its used in baths, dry wall cant take moisture alot we have family right now used drywall and thier bathroom walls are moldy and yes they have ventilation.


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RE: Green Board or Not???

Mold is a surface problem. How is putting wax on the drywall (what greenboard is) going to prevent mold?
Whatever vetilation they have is either not adequate or not being used.


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RE: Green Board or Not???

No, theres moisture IN the walls.Wax lets water bead up... GO BACK TO YOUR REPAIRS.Weve been in building business over 40 years,Im not gona argue with a repairman.We do it right the first time.Brickeyee Is that a mason?


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RE: Green Board or Not???

Look up cement board on internet....


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RE: Green Board or Not???

Cement Board for a tile backing of course. I'm not going to tile the whole bathroom floor to ceiling. The walls where it's not going to be tiled, the drywall contractor is saying regular drywall instead of green board. He says no more green board as an industry standard.

I'm a General Contractor and a plumber by trade. This no green board is new to me, and as I'm finding out it is becoming more and more of a standard.


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RE: Green Board or Not???

Are your little feelings hurt?

Greenboard was a flop from day one.
It does not offer enough moisture resistance for any purpose. Its use has come to a grinding halt with good reason.

Water IN the walls had to get there from somewhere.
If the ventilation is adequate how did it penetrate and accumulate?

I have been building, remodeling, and repairing houses for over 30 years now.
I do not just do repairs, but have a rather successful business with word of mouth for all sorts of work.

You better get a grip on yourself.


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reRE: Green Board or Not???

And I guess you know all about IRC R702.4.2 that limits 1/2 inch water resistanrt drywall under tile to 12 inch span?
Guess we should not even need that code provision since no one would do that.


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RE: Green Board or Not???

Nope not at all.....no hurt feelings here.


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RE: Green Board or Not???

I really do not understand why you have your panties in such a wad.

Cement board is NOT greenboard.
Are you confusing the two?
Unless you apply Keens cement or a setting joint compound to the cement board you have not really gained anything.

Ceramic tile is waterproof (not damaged by water) and depending on grade and type may be impervious to water penetration. The grout joints are not impervious to water penetration though, and whatever the tile is mounted on needs to be able to resist damage from the water that gets through the grout lines.

Greenboard is wax coated gypsum wallboard (more generically know as water resistant gypsum wallboard). It is used in low quality work as a tile backer. Since tile is not waterproof and the wax coating is not adequate, tile walls with greenboard as a substrate have a history of failure after 5-8 years.

Cement board (Wonderboard, Durock, etc.) is fiberglass reinforced Portland cement made into boards. It is waterproof to the extent that it is not harmed by water, but it does not stop the flow of water well enough to be used by itself in shower walls or places subject to repeated wetting without a moisture barrier between cement board and the rest of the structure to prevent long term leakage. 15 pound felt is adequate as long as the bottom edge is within a drainage area (inside tube edge, inside shower pan, etc.). In many cases it is just as easy to run the shower pan membrane all the way up as high as the tile will be used.

I have been in business as long as you have as a PE running a consulting company, building, and remodeling. New work and old, medium to high end, houses and commercial technology work.
I just actually finished a mud bed jobs in 6 bathrooms in a high end house after tearing out two kitchen floors worth of tile on other jobs.
These are pretty small potatoes though, and just keep the guys busy. Most are not interested in working on tract houses going up in the area.
The pressure to perform a cheap job and cut corners is not worth their time.
When they need a structure modified to take stone floors they turn the job over to me, and then I sub back to them the stone work.

I guess you have performed a mind-meld with your husband and have all his knowledge in your head nowI hope the attitude is not his also.
I see all sorts of stuff, both in rebuilding and in consultation (sometimes for law suits).
The general quality of work has continued to decline over the past 30 years for many trades. The high end work remains as good as ever, but to bring the work within reach of more customers corners have been cut.

Cement board is almost as good as a mud job. Mud jobs rarely need moisture barriers since the cement is more than thick enough (minimum 2 inches) to prevent any significant penetration, but being a little paranoid lately I cover all the wood members with either paint on membrane or 15# felt.
Cement board is thin enough a barrier is required to protect the structure from moisture that gets through.
I have not done a mud bed job in a house under a million though.

Greenboard was touted as the new underlayment for ceramic tile. Many builders bought the marketing crap. Problems showed up in as short as 3 years after installation.
Water penetrated, softened the gypsum core, and tiles started falling off walls in showers.
The only fix is to rip all the greenboard out and install cement board and barrier, followed by a new tile job. Some folks elected for fiberglass modular showers and tubs since the cost was lower.

Funny how those 1950 and earlier mud bed jobs seem to have held up so well.

"My hubby is a builder I asked him he said no they now use cement board instead."

Glad you found some time before he fell asleep at the end of the day to answer a question.
Applying cement board to a bathroom wall and painting it is a pretty big waste.
Guess your customers do not care about the expanse.

"Weve been in building business over 40 years,Im not gona argue with a repairman.m "[sic]

I am not going to argue with an unhappy housewife who sits around belittling people who she knows nothing about on subjects she has to ask her husband for an answer. Have you been in business or your husband? He sounds like the one who does all the work.

"Brickeyee Is that a mason?"

No a PE with a PhD in engineering. No repairmen anywhere here.

Sit back and have another bon-bon till your husband gets home.


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RE: Green Board or Not???

You seem to have plenty of time on internet ,HOW DO YOU GET ANYTHING DONE???he doesnt use the computer,We have a real model home with an office.......No as a matter of fact we own 2 construction companys.One high end custom homes,we do modulars for 4 different companys,we install pools,and agricultural buildings.Hes does a little more than you it sounds.Youre the one with panties twisted I wasnt talking to you I answered someone elses question.....Now go play in your mud.....


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RE: Green Board or Not???

"Hes does a little more than you it sounds."

I really doubt it. HVAC, plumbing, electrical, radiation effects testing and research, wood structure design (including mixed wood steel), remodelling, restoration work, it is well up in the 10s of millions now.

I have crews and supervisors to handle the job sites and directly employ 10 people, and support about 20 companies and government contracts.

You personally do not know what you are talking about.
"My hubby is a builder I asked him..."

"I wasnt talking to you I answered someone elses question.....Now go play in your mud....."

You have a real attitude problem.
I would suggest you get over it.
Are you working in the business or just whining your husband works hard?


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RE: Green Board or Not???

same here.........


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RE: Green Board or Not???

Good lord! Do you two need to take this outside or something? :) Honestly, it's quite entertaining, but only in the way that pro wrestling or COPS is entertaining... I think you BOTH need to get over yourselves, sheesh!!!


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RE: Green Board or Not???

Ok,

Everything here has answered everything except on question. I have a upstairs shower in a brand new house that has cracks in the grout. This cracked grout is located on a 36" half wall that acts as a divide between the shower and the tub. This 36" wall between the tub and shower is no longer plumb. The home builder wants to demolish that wall, make it plumb, and apply green board against the wood wall, then apply cement board over the green board. I had suggested to the home builder that I would rather put 15 lbs felt over the wood wall, then put the cement board over the felt, but the home builder said that they would not do that. So, my question is....which option would provide the best protection.....wood, then green board, then cement board.....or wood, then 15 lb felt paper, then cement board ?


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RE: Green Board or Not???

Tar paper (15# felt) provides a perfectly adequate water barrier.
The bigger issue is how will water on the paper drain?
Cement board and tile will allow water to penetrate thourth the grout and into the backer board.
Tar paper provides the barrier to prevent the water from moving any further into the framing. If it is applied correctly from bottom to top with overlap between courses the water will drain down.
You need to ensure the water has a place to go at the bottom of the felt.


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RE: Green Board or Not???

This is the US Gypsum site, the largest maker of drywall products in the world.

Read their new limitations on greenboard.

Here is a link that might be useful: Green board


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RE: Green Board or Not???

Say -

I have signed on with Re-bath to bond their acrylic surround to my existing greenboard wall around my shower tub combo. They say that the commercial strength adhesive renders the surround completely waterproof. Shoud I believe them - or insist it go over cement board?


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RE: Green Board or Not???

1st Question--Do I need greenboard in nonshower areas or is there a better material? We have a small area that will not be covered if we use greenboard b/c the old tile goes up too high so we can eitehr use regular drywall or leave space at bottom to cover with baseboard. Or maybe there's some other material that is better than regular drywall but is not greenboard? i read on this forum about a yellow board??

2nd Question--do i need a membrane or vapor barrior over the Durock/hardibacker/wonderboard (not sure which he is going to use) in the shower? I had heard that they can actually trap moisture and thus defeat what you had intended to do? Three of the four shower walls are interior walls.


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RE: Green Board or Not???

Humitek is one brand of moisture resistant panel. If it costs no more than regular drywall, it's worth it. However, there are so many cautions in the manufacturer's description that I wouldn't have great expectations. It is also recommended to put a vapour barrier behind the cement board.

If you have the budget, the surest system is a waterproof membrane, such as Kerdi.

No matter what you use, provide ventilation in shower areas to the exterior via a fan. A window alone is not much use.

Here is a link that might be useful: Greenboard


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RE: Green Board or Not???

US Gypsum no longer makes MR Board or Humitek and has substituted Mold Tough with a green face. Other manufacturers still make MR Board with a core and face paper treated to resist moisture with a green face. I assume this is the product being discussed here.

The appropriate use of MR Board is clearly defined in the manufacturer's specifications. The recommendations below are from National Gypsum (Gold Bond).

MR Board can be used as a tile backer board in dry areas or areas with limited water exposure such as toilet/sink areas and areas above tile in tubs and showers. It may be extended beyond the area to be tiled.

The special moisture resistant surface is specifically designed to accept tile adhesives while resisting the effects of moisture.

MR Board should not be used as a backer board directly behind tile in tub and shower areas. It should not be used in areas subject to constant and/or excessive moisture and high humidity or heat such as gang showers, saunas and steam room and swimming pool enclosures. Cement Board is recommended for these applications.

A vapor retarder should not be placed behind MR Board when used as a tile backer. A vapor retarder can be created on the face of the MR Board by applying a skim coat of tile adhesive or by using silicone grout for tile. By itself, MR Board is not a vapor retarder.

MR Board should not be used on exterior ceilings. It may be utilized on interior ceilings provided spacing of framing members does not exceed 12" o.c. for 1/2" MR Board and 16" o.c. for 5/8" MR Board.

So, in a few words, it is recommended as a good substrate for ceramic tile in the dry areas of a bathroom and requires special attention on an exterior wall that needs a vapor barrier. Always use a cement/concrete backerboard in a shower.

Do not use a fiber-cement backerboard in a steam shower.


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RE: Green Board or Not???

Building Science Corp. says this:

"Gypsum wallboard - Areas of potentially high moisture, such as bathrooms, laundry rooms, and kitchens are excellent candidates for non-paper faced wallboard systems (e.g. James Hardie's Hardibacker�, GP's DensArmor�, USG's Fiberock�). In addition, paper-faced gypsum board should never be used as interior sheathing or backer for tub or shower surrounds where ceramic tile or marble (any material with joints or grout lines) is used as the finish."

However, Kerdi, a waterproof membrane, can be applied directly over paper-faced backerboard. As an experiment, I used this in one bathroom in the last home I built--along with the preformed foam base. It was a very straightforward application for the installer, who had never worked with it before. Just follow the video. For the other baths, I used a non-paper faced drywall and conventional mortar bed. I think I'd use the Kerdi on the walls again. But whether or not I used the base would be a matter of comapring the total cost of a conventional base, which requires more labour vs Kerdi--base kit came at $550 but virtually no labour.


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RE: Green Board or Not???

mightyanvil said: US Gypsum no longer makes MR Board or Humitek

Humitek is available from Canadian Gypsum.

It was $18.97 a 4x8 sheet at HD today, the same price as Durock.


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cont.d

Sorry. Try this link: Humitek.


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DURAROCK question

We are re-doing a shower in our home. Do we need something MORE than DURAROCK cement board over the framing, topped with our thinset and travertine? Is there a barrier paper that should go on? Cement board is already up, not coming down. Anyone?


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RE: Green Board or Not???

If the cement board is not coming down the issue is moot.


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RE: Green Board or Not???

I just happened upon this forum, only because I'm now under contract for a 100 year old Victorian home here in town, and thought I'd look around for any useful information, and I ran across this thread. Time to dispel a few misconceptions:

And I guess you know all about IRC R702.4.2 that limits 1/2 inch water resistant drywall under tile to 12 inch span?
Guess we should not even need that code provision since no one would do that.

Sorry, my friend, but that only applies to ceilings.

As for the whole cement board/ greenboard thing, cement board MUST be used in wet areas. As of a couple years ago, it's now code:

IRC Greenboard Code:
The 2006 International Residential Code (IRC) states in
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."

The 2006 IRC also states in Section R702.3.8.1 that
"Water-resistant gypsum backing board [Greenboard] shall
not be used where there will be direct exposure to water."

As for using greenboard in the rest of the bathroom, yes, it can be, TILE OR NOT. Thinset (and mastic, which CAN be used on walls in non-wet areas) will both adhere very nicely to both greenboard AND standard sheetrock.

The home builder wants to demolish that wall, make it plumb, and apply green board against the wood wall, then apply cement board over the green board. I had suggested to the home builder that I would rather put 15 lbs felt over the wood wall, then put the cement board over the felt, but the home builder said that they would not do that. So, my question is....which option would provide the best protection.....wood, then green board, then cement board.....or wood, then 15 lb felt paper, then cement board ?

Even better than the tar paper underneath would be using a paintable waterproofing agent, such as Custom's Redgard. Being that it's a halfwall, you're going to get water sitting on top. You need to make sure there's protection for that entire wall (on the shower side) as well as the top. The Redgard would do that for you.

We are re-doing a shower in our home. Do we need something MORE than DURAROCK cement board over the framing, topped with our thinset and travertine? Is there a barrier paper that should go on? Cement board is already up, not coming down. Anyone?

I'm PRAYING you have at the very least a pan membrane that's presloped and goes up 8-10" behind the Durock!! What SHOULD'VE gone behind the Durock is either tar paper, or 6 mil poly to be used as a vapor barrier. If the Durock's up and not coming down, what you can do is go over the surface with either Custom's Redgard or Laticrete's 9235 or Hydroban.


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RE: Green Board or Not???

bill vincent I knew the handle was familiar from somewhere--John Bridge.

btw, Do you have any preference between Denshield or cement board?


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RE: Green Board or Not???

I don't care for Denshield at all. To me, it's a new twist on an old theme. It used to be MR board, that had a green moisture resistant covering on a gypsum core. With Denshield, now it's some kind of plasitc sheeting over that same gypsum core. I'll stick with Durock, thank you. :-)

Yeah, I might visit John every once in a while. :-)

Photobucket

he and his wife are traveling around the country right now, and are going to be visiting up this way probably the end of september..... just in time for me to close on the house. :-)


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RE: Green Board or Not???

Of course the main thing to notice is that if you put a piece of Denshield in a glass of water it will not fall apart. Quite different than the old Green board.


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RE: Green Board or Not???

Bill Vincent, you missed the fact that Brickeyee was talking about ceilings: "There are also rules limiting its use in ceilings cause it sags so bad. In many cases you would need ceiling joists on 12 inch centers to use the stuff."

Also you refer to a code requirement for cement backer board that allows the use of a glass mat gypsum backer board adding to the sloppiness of the discussion.

The original question was about a shower half wall that would probably not get much exposure to water so the nature of the substrate should be of minor concern since water is unlikely to ever fully penetrate the cement backer board.


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RE: Green Board or Not???

"...water is unlikely to ever fully penetrate the cement backer board."

Enough water can wick through the grout joints of tile and then through the backer board to studs.

Wither a barrier on the face of the cement board (Ditra, applied membrane) or a barrier between the cement board and the studs is still needed.

Cement products are not damaged by moisture, so they are 'waterproof.'
They do not stop the movement of water however.

Even pools are coated with plaster to limit water movement through the concrete on the sides, and often tile on the bottom so the only leakage path is through the grout and not the entire pool bottom..


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RE: Green Board or Not???

My point was that if water from a shower head was able to penetrate a tiled low half wall and saturate the cement backer board next to a toilet, it is likely that the toilet area would already be flooded creating a more serious design problem.


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