My Home Depot Tiling 1-2-3 book says that I need to use cement backer board in the bathroom.
In addition, I hear references to using greenboard in bathrooms from time to time (and I see it available at HD).
BUT
I have never seen a bathroom that actually used either! In all of the bathrooms where I have seen behind the tile (e.g. during construction or while tearing it out), I have seen tile affixed directly to plain old wallboard.
What’s the SD on this? Is it really necessary to use cement backer board behind the shower walls and greenboard for everything else in the bathroom, or is it simply “the right thing to do” that no one really does?
What will happen if I redo my bathroom walls with regular wallboard and stick the tile directly to it? My bathroom has lasted 40 years with this configuration and developed leaks a couple of years ago mainly due to old grout. Will it last long enough for me not to care?
Moisture resistant wallboard may meet code for tub and shower enclosures as a backer, but it’s still not good practice. Having repaired too many shower enclosures and tub walls where the substrate failed, I refuse to do new or repair work unless I’m hanging cement backer board. Durock-Hardie-Eternit are all equally good. Just make sure that you attach the board per manufacturer fastener schedule along with any and all other prep per the TCA handbook. For walls not in the tub/shower area, you can get away with MR board as a tile mounting substrate.
Not a contractor, but I did help my father retile the tub and shower in a bathroom. It started off as a Labor Day project to regrout some of the tiles but that quickly came to an end when the tiles basically started falling off the wall due to the wet drywall. I don’t know what was holding those tiles on there other than sheer inertia. So yeah, I’d go with the cement backer board, even if the code doesn’t require it. Might as well do it right the first time and I swear that it’s actually lighter than drywall. It’s probably not, but it’s far more pleasant to work with than gypsum.
If I’m not mistaken, cement board hasn’t been around all that long. In those decades between the invention of wallboard and the invention of cement board, I think it was standard practice to put tile directly onto wallboard. It’ll usually last for a good couple of decades, but when it goes, it gets pretty ugly. But there’s no reason to use cement board for anything but the shower/bath area, I would think. Greenboard should do nicely for the rest of the bathroom.
In a kitchen, you get away with it as it it just splahes and stuff. But in a bathroom, any grout breach can become major trouble.
Do the right thing and get a cement backer. Also, choose your adhesive well. Some folks use mortar over mastic, even on walls, as it is more hardy against water.
Not exactly…depends on whwere you’re from, I guess.
I’ve seen installations where actual cement was used as a backer…you know, that stuff you mix with water and then spread around with a trowel? Yeah, that. Yes, on the wall…I’m not kidding
That’s the way the true Italian tile installers do it. The “masters” won’t mess with cement board. They mix up the cement, trowel it onto the screen that is attached to the wall and throw the leftover cement under the tub. After everything is tiled and grouted you have a “real” bathroom. My contractor brought in “Nick the tile guy” to finish the kitchen and bathroom and it was amazing to see this guy work the floors and walls with cement to make sure everything was perfectly even for the final tile set. He wouldn’t set a floor on less than 4 inches of concrete. A true craftsman!
In more modern construction methods anybody that doesn’t at least use cement board in bathrooms and in the kitchen areas near water is beneath contempt. Cement board can also be an excellent underlayment for floors.
I guess that’s it then. I’ll use cement board. Just checking if I was doing something silly.
There’s a thread going on now about guitar maintenance, and some folks there have mentioned carefully removing and replacing each string one at a time so as not to stress the instrument. I know well enough that my guitars are fine if I take all of the strings off at once, so I don’t burden myself with the extra trouble. I was just wondering if the backer-board is a similar “those in the know don’t worry about it” kind of thing. Apparently not.
Finagle, As to why I would even consider not using greenboard everywhere, since it’s so cheap… I have 3/8" wallboard, but I have only ever found 1/2" greenboard. So to do it right I would have to gut the bathroom completely. That said, I am considering ripping everything out and doing a proper job of it, so that I can sleep at night knowing that my bathroom will still be around in forty years.
Ugly is an understatement. We were washing Spot the Wonderpup, and my husband leaned on the soap dish. Suddenly, a big chunk of wall fell into the tub. (Scared the bejeebers out of Spot!)
Behind the tile was wet wallboard. Behind that was a layer of thick black mold. Behind that was another layer of tile. Behind that was plaster and lath. And behind that, stuffed between the studs, was a newspaper from 1951!
Yecch. What a mess.
We were able to pull out most of the gross wet moldy stuff, put in cement board, and re-tile on top of that. Since we were planning to do a full bathroom renovation (to the bare studs) within a couple of years, we didn’t bother to re-do the whole thing. The full renovation has since been done, and I am much relieved not to have to worry about wet moldy wallboard lurking in my house.
See, that’s the whole point. It’s not enough to cover the problem for awhile, you need to prevent future problems. Mold growing inside your house is not a good thing for either you, your family or your resale potential. Who says that somebody can’t come up with a gizmo that will detect unseen mold (maybe it exists already)? So you get by for 10 years, decide to sell the place and someone figures out that the bathroom is a disaster and knocks down your price by 20%. Now balance that against the price of a few sheets of cementboard.
Perhaps that is based on one’s definition of “that long”. IIRC, Durock 1/2" was the original CBB and it’s got to be 20+ years old. The 1/4" and 3/8" CBB from Eternit is at least 15 years old.
You’re right-it was standard practice to attach tile directly to regular board. What I don’t understand is why older homes (pre 1960) will exhibit partial bond failure and board disintegration now, and newer construction (1980’s and up) is already exhibiting failure.
Note to minor7flat5: Not positive you can buy MR board in 3/8" Typically 1/4 and 3/8" are standard boards, 1/2" is standard and MR, and 5/8" is fire-rated. If you have an area of 3/8" wallboard which has failed and you’d like to evenly blend to the adjoining wall plane, strip the board to the studs, add 1/8 rip strips (if you have access to a table saw-make your own) and then install 1/4" CBB over them. Install your tile and everything will be where it should.
You omitted relevant parts of my post without noting that you had done so.
We “covered the problem” for approximately 2 years, and then ripped out the entire bathroom down to bare studs. All the new tile is installed properly.
I’d be a little leery about putting tile on quarter-inch greenboard. That stuff is not very rigid, and I’d worry about the wall flexing (and breaking the grout lines) when somebody leaned on it. Have you had success tiling board this thin? I think the 3/8 cement board would be preferable.
Actually, I’m not sure that quarter-inch greenboard even exists. I just looked on the sites from the major manufacturers, and the minimum seems to be half-inch. So ignore the above.
I wasn’t criticizing, I understand what you did and why you did it. I was citing your experience as a prime example as to why the OP should not do a fix that will look good for awhile. Your experience demonstrates how poor construction can contribute to problems that are much more serious and be very costly in the future. (Also, Spartydog empathizes with and sends his best regards to Spot the Wonderpup.)
Whenever anyone is tempted to cut corners in construction you should talk to an experienced building restoration person. There are huge problems out there where corners were cut in new contruction. A lot of restoration work is done on recent construction. Of course, the restoration costs become exhorbitant but only because someone didn’t do what they should have done or outright cheated.
