When was “green board” banned from showers and wet areas to be replaced with required waterproof material? I don’t remember!
I need to know this because I’ve been asked to repair a shower in a house built in 2003. Home owner had asked builder if the green board was the right stuff to use.
Listeners write in about paint strippers, bricks, and FHB Podcast volume and ask questions about insulating under membrane roofs and whether waterproofing prevents concrete foundations from drying.
"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
According to the Shluter Kirdi people, green board is ok if you then use their product.
I still use cement board around tubs and in showers.
I don't know that this is a code question. Most building codes specify that materials are to be installed per manufacterer specifictions. The question is has green board ever been specified for use as a direct tile substrate in a shower by the manufacterer?
As a builder I think you are getting into the wrong business if you are being an expert for possible future litigation. Let them hire a lawyer and figure it out. I have thought that green board is the cheater method since the first time I saw it and would say that to a customer. Being the "expert" will only benefit you if you are upselling your higher quality services.
Ask your code question here: http://www.johnbridge.com
It's an indirect code question in the sense that the code requires conformance with the TCNA Manual, so it's really a question of when TCNA stopped showing greenboard in certain configuration details.
Update - see 100452.13 below
Jeff
Edited 2/6/2008 1:40 am ET by Jeff_Clarke
Banned as of the 01 Jan 2006 revision.
Jan 2006 of what code?
Not to sound stupid, but what codes says you can't?
I dont but worked for builders for years that did.
See IRC 702.3.8, that section tells you where you can't use greenboard, and when you can what restrictions you have to conform to.IRC702.4.2 tells you what materials are approved as a tile substrate in wet areas. Greenboard isn't one of them.And whoever wrote it is correct, TCNA methods are guidelines, not code. However, while the code is stagnant and sometimes slow to evolve, TCNA is a bit more progressive, and code is sometimes changed to meet TCNA methods.Example, my local code is IRC, but when more restrictive local amendments are added, they might be modeled after the TCNA guidelines.
I am in no way advocating the use of Moisture resistant (MR) drywall behind bathroom shower tile however I am going to answer your question from strictly a code standpoint.
First, someone above sited the IBC - International Building code. This may be different in other states but here the IBC is used for commercial buildings. Not residential. IRC (International Residential Code) 2003 is the model code (with modifications) is the one used here in NC for residential applications. The modified sections are marked in our NC flavor of IRC2003 however none of the following is marked:
IRC2000:
Looking at my IRC2000 book section "R702.3 Gypsum board" does not restrict the use of Moisture Resistant (MR) drywall. Section "R702.4 Ceramic Tile" talks about MR drywall but just says that it has to conform to ASTM 630 which is just a standard for MR drywall.
IRC2003:
Now, looking at my IRC2003 "R702.3 Gypsum board" still does not have any reference to MR drywall, and does not contain the IRC2006 R702.3.8 that Mungo refers to. In Section IRC2003 "R702.4 Ceramic tile" a new paragraph is added (not in IRC2000):
R702.4.3 Limitations. Water-resistant gypsum backing board shall not be used in the following locations:1. Over a vapor retarder in a shower or bathtub compartment.2) Where there will be direct exposure to water, or in areas subject to continuous high humidity.So, this is where the code comes into effect that prohibits the use of MR drywall in showers although the terminology: "Where there will be direct exposure to water," could be up for debate.
From IRC 2006:
Going on to look at IRC2006:
R702.3.8 (new in IRC2006) Water-resistant gypsum backing board. Gypsum board used as the base or backer for adhesive application of ceramic tile or other required nonabsorbent finish material shall conform to ASTM C 630 or C 1178. Use of water-resistant gypsum backing board shall be permitted on ceilings where framing spacing does not exceed 12 inches (305 mm) on center for 1/2-inch-thick (13 mm) or 16 inches (406 mm) for 5/8-inch-thick (16 mm) gypsum board. ASTM C630 is a standard for MR drywall, but this paragraph does not prohibit the use of MR drywall behind tile, however read on.Water-resistant gypsum board shall not be installed over a vapor retarder in a shower or tub compartment. Cut or exposed edges, including those at wall intersections, shall be sealed as recommended by the manufacturer. Here it only says don't use MR drywall over a vapor barrier, but again, does not prohibit the use of MR drywall.R702.3.8.1 Limitations. Water resistant gypsum backing board shall not be used where there will be direct exposure to water, or in areas subject to continuous high humidity. Again, not in IRC2003. Still a little vague, although I guess shower walls are subject to "direct exposure to water".More to the point, this next paragraph is completely changed from IRC2003 which was called "Gypsum backer":R702.4.2 Cement, fiber-cement and glass mat gypsum backers. Cement, fiber-cement or glass mat gypsum backers in compliance with ASTM C 1288, C 1325 or C 1178 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. Here it says use cement backer board, etc, in tub/shower areas, but again doesn't mention MR drywall
Summary:
Clear as mud!!! So in 2003 and 2006 they have added paragraphs and new verbiage about MR drywall, but in typical code fashion, they never really come right out and say "Do not use MR drywall in showers". although I think the text "direct exposure to water" that is new in 2003 would be interpreted by most all code enforcement officials to mean showers.
USANigel: First thing you need to find out is what code is used in your state, and secondly when specific codes were adopted. In NC IRC2000 was adopted 1/2002 and IRC2003 was fully adopted 1/2008!
Matt,
By the 2006IRC 702.4.2 stating that only "cement, fiber cement, and glass matt gypsum board" are allowed as tile substrate in wet areas, it excludes greenboard.
The 702.3.8 would not be included in the 2003 version since it dodn't come out until 2006 ammendment.
Best bet would be to look at the 2006 IRC ammendment in and of itself. You're correct, the 2006 ammendment conflicts with the 2000 and 2003 versions, because it updates them.
Wanted to add: you're not alone. There are a bunch of very good tile setters that still are ignorant about setting tile over greenboard...out of ignorance.And a lot of bad folk who set tile over greenboard...out of apathy.
Ahh, Ignorance is blissful!
Thank god I have been doing it right since on my own, but built hundreds and hundreds of homes for years working for others with greenboard. (as super, PM, and VP)
I continue to learn stuff when I just open my IRC book but the only thing I remember learning about tile was that gaging the pan prior to vinyl is required.
BTW, same laws in PA re IRC, 2006 was adopted but there are a couple of state ammendments (stair code) and local ammendments that were in place since 1999 if locality maintaned the ammendment. (most have not and cant get any others passed as the HBA's fight them pretty hard)
Thanks for quoting it for me since I was being too lazy to open up my IRC book!!
Does the shower in question have tiled walls, or some other approach?
It appears the deep thinker who did the work used green board to rock the whole bathroom including the wet areas.
When you look at the tiles, very cheap 8x8, some are discolored at the bottom row. I've seen this before and I believe they are soaking wet. The house was replaced in 2003 due to a fire and I knew the code had changed to ensure green board would not be used under tile in wet areas. I could not remember when, the home owner wants to go after the builder for the cost of correcting this.
Whole shower area has to be rebuilt for sure.
Edited 2/5/2008 8:56 pm ET by USAnigel
Certainly it's been known since the 60s or 70s that greenboard is insufficient behind tile used in a shower surround. Cement board became available ca 1980 and eliminated any excuses for resorting to greenboard. Allowing for the time for the information to trickle down, I'd say that anyone who used greenboard for a shower surround after 1990 was either incompetent or fraudulent -- they knew (or should have known) that it was going to fail, and they knew of a better (and not much more difficult or expensive) way to do it.
If your view never changes you're following the wrong leader
Well I used it in the early 90's which makes me incompetent - because I sure didn't make any money after doing the subsequent repairs, so at least I'm not fraudulent.
Code refers to the recommendations of the TCA [Tile Council of America] Handbook and ANSI standards [A108 Specifications for the Installation of Ceramic Tile].
Not everyone follows TCA. Thats the bad news.
This question piqued my interest so I got off my #### and looked it up.
As of the 1997 Uniform building code it is allowed 2512 it is prohibited in saunas, steam rooms and gang showers. It also shall not be used over a vapor barrier.
As of the 2000 International building code it is also allowed per 2509.2
As of the 2006 International Building Code it is not allowed per this wording
2509.3 Limitations. Water-resistant gypsum backing board shall not be used in the following locations:
1. Over a vapor retarder in a shower or bathtub compartments.
2. Where there will be direct exposure to water or in areas of high humidity.
3. On ceilings where frame space exceed 12".
The 2006 is the most restrictive that I read. It also is up to interpretation. If tile is protecting the drywall it is not neccesarily direct.
These would also have a lot to do with when a specific code was implimented in a jurisdiction. In my area we are still on the 1997 but are slated to move directly to the 2006 IBC as of July last year. It still has not been properly adopted.
Your customer would have to make a case about it not being industry standard, they would also have to show how they were injured by this negligence. Just more ambulance chasing if you ask me.
Jason
Thanks Jason, I wondered what the history of this was. I did read somewhere the green board should be skim coated first and this let cure, then tile. Then it might last for a while. Its all alittle too hit and miss and is only waterproof by luck!
I did read somewhere the green board should be skim coated first and this let cure, then tile. Then it might last for a while.
The book I have, Setting Tile (Byrne) [http://www.amazon.com/Setting-Tile-Homebuilding-Michael-Byrne/dp/1561580805/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1202337702&sr=8-1] explicitly says that greenboard is NOT a suitable substrate for tile in wet locations.
I think what most people have said here rings true: professional tile installers have known for a long time that greenboard is inadequate for tiled shower walls. I'm not sure what the builder in your case was thinking, but I know lots of people make honest mistakes, so I wouldn't automatically assume he was using an inferior product to save money. After all, the cost difference between using concrete backer board and green board is probably less than $30. With that in mind, I'd say the odds are it was an honest (but ignorant) mistake.
It sounds like it's allowed to me too Jason99. Bob's next test date: 12/10/07
PS:
please tell us what code is used where you live.
The work in question is in Berlin, NJ. I think we're using a version of 2006 International Building Code. I'm not sure what was being used in 2003 when the job was "done".
Many many thanks to all for you input and help with this.
Really, it doesn't sound like you got your Q answered. Sounds like you maybe need specific information from the NJ version of the IBC2003 and to find out when (if) IBC2003 was adopted in NJ.
This link showing current NJ building code might be usefull in the future...
How about maybe you put your general location in your profile. BTW "the code" for shower walls in Zimbabwe is that all bathrooms be constructed out of concrete block.
Thanks Matt, useful info. I think its a waste of time going after the builder for his crappy work, but worth asking about.
You don't want to be involved.
Along that same line, I make it a point not to comment about other people's work or at least say as little as possible.