Just discovered that water managed to get behind the tiles of my kids bathtub, soaked the green board and rotted it out. Looks like it extends up about ~3 feet. Pulling away tile and board, I appear to have some sort of thin barrier/paper on the other side of the green board and then drywall behind that attached to the studs.

Plan unless someone suggests differently is to cut a bit above the dry line and remove the tile, green board and possibly dry wall depending on what condition it is in.

I have been told that now days, there is a better alternative to green board... Anyone know what it is called? And can it be cut with a circular saw? I would like to cut it to fit flush after installing some sort of vapor barrier (15# roofing felt or something else?), tape the seams, and then retile.

Anything I am missing that is going to create misery for me?

Thanks Ags

You probably want cement board which can be scored, cut, and installed very similar to sheetrock.

Google cement board or "DuRock" and you will find lots of info on how to install it, but if you've ever done sheetrock, it will be very easy for you.

Cementboard, and you'll need a special blade but it can be cut with a circular saw... tho it's probably easier to just score and cut it like drywall. You'll also want to use a waterproof membrane (Kerdi is the one I see recommended a lot) ... I have not done this myself, but what I remember from watching it done on TV is that you lay a thin layer of thinset over the cementboard, put the kerdi over it and smooth over it with a grout float, and then put your mastic or thinset and tile on over the kerdi.

The basic gist of the difference between cementboard and greenboard is that there's NO organic material in the cementboard that can rot, so even if a little water seeps through, you're OK. OTOH, the wood studs behind it can still rot, so you don't want tons getting through.

[This message has been edited by superspeck (edited 8/10/2010 12:50p).]

You can do what you describe. Keep in mind that it will be obvious that it was repaired, but it is not an uncommon repair in older homes.

Teh cement board is available at HD or Lowes. It is hard to work with and you may end up with a thickness problem, so check that when you buy.

cement board, then tape and thin coat all joints and corners...then a layer of membrane(comes in a gallon can just like paint)that is rolled on like paint and the tile go on top of that. I watched the tile guys do these steps when we redid a stand up shower stall two years ago. Blue membrane for the walls and heavy duty black for the floor

I only work in commercial.....BUT.....I would not think you need anykind of a membrane on a wall. Just tape/float out the cement board backer and use a waterproof mastic to adhere the tile. I would think that sufficient unless you have water standing, which on a wall you should not.

[This message has been edited by RoperJoe02 (edited 8/10/2010 4:50p).]

Thanks Ags for the information and advice!

quote:

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Keep in mind that it will be obvious that it was repaired

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Absolute: Why would it be obvious if I used the same tiles as are currently in place? If it is too obvious, I may instead take out ALL the tiles to the very start and just start fresh.

this same stand up shower shifted with a slab crack in 1982 but the damage wasn't evident for a couple of years until the lead pan leaked....

it was replaced and PETRO, the bottom two rows of plain white 4x4 tiles were removed and it was impossible to match the new and old tiles, even with a small decorative break up.

Ten more years pass and another leak formed and the damage was in the adjoining drywall. All that mess was repaired.

ALL THIS WAS DONE BY PAID PROFESSIONALS!

In 2008 I painted an adjoining bedroom and found drywall damage in there....damage to studs and another lead pan leak. Hubby tore everything out to the wall studs and replaced all the damaged wood. He then added cut to fit foam board insulation and then the cement board. After he had all the walls up the tiler came in and did the membranes top and bottom that I previously described.

FWIW, after all this experience trust me, you cannot be too cautious or too dry. Tearing out two rows of tiles is just as messy as taking the shower to the studs it only takes longer to get finished! Rip it out choose something that will reward your efforts when it it finished and do it right.

There will be a depth problem if you try and use cement board instead of greenboard, as the former is actually thinner.
I agree with the above posters that you will not enjoy the look if you try to match new tile with the old. Tear it all out. From there, check for rot on ALL of the studs. If you're okay there, (it is my experience) that you should hang a water barrier (I use plastic sheeting) where you will be tiling. Next, SCREW the cement board straight to the studs. You may need to pick up screws that are specially designed for this part. Then tape any seams you have while paying special attention to put a small amount of sylicone on the screw-holes and seams. Finally (using a water-proof adhesive) apply tile, grout, and treat said grout with a water-proofing treatment.
It's actually pretty easy and you'll appreciate it more than trying to match tiles. Everyone does things differently, and I am sure some will have differing methods than I. This is just how I've done it in the past, and it's always held up well. Good luck, let us know how it turns out.

Thanks Mom & Sgt.

Probably not a huge deal to also tear out the top 2/3 of tiles if matching will be as hard as y'all indicate. Even in the worst area right at the base of the tiles and top of the tub, the drywall located behind the greenboard didn't have any moisture so hopefully that means that the studs will be in good shape.

+1 on tearing it all out. It doesn't help anything if you have to do it again soon.

Just depends on your plans for the house and stomach for the work. More work and cost to do it all, but it will look much better in the end. As stated above, the matching thing is always a problem. Unless you have enough tile left from the original batch it will not match.

Doing the whole thing is a long weekend (or maybe two weekend) type project. It is not terribly hard, but it gets a little messy and you will learn some things as you go.

I would agree that the membrane would be a bit of over kill on that type of shower, but it certainly would not hurt. If it just paints on, you might as well add it. Last time I did it I just used the additive to the mastic, but that was 15 years ago.

Oh, and if you or your wife has any desire to see a different type of fixture - this would be the time to do that too - if you replace the whole thing.

[This message has been edited by Absolute (edited 8/11/2010 1:03p).]

IT IS MORE THAN A LITTLE MESSY...you will have grout dust everywhere, even inside drawers you don't open..............don't want to scare you away from doing this the right way but is was a buttload of messy! A really big butt at that!

>>I would not think you need anykind of a membrane on a wall.<<

If you want it to last pretty much the life of the house, you do.

It doesn't cost a lot more to use both concrete board and a membrane. It doesn't take too much more time. If you do it right, you won't have any problems with moisture, ever. Why wouldn't you do it?

Not telling them NOT to do the membrane....just don't think its necessary. If you have water getting through the tile/grout then you have other issues. FYI.......commercial construction is designed to last, and commercial applications (i.e. showers used in schools, locker rooms and other considerable use areas) typically don't use a membrane on the walls, though we do recommend "uncoupling membranes" on floor tile. Salesman have done a great job of selling things as necessary when fundamentally there is no reason for them. If your not worried about a few extra bucks and a little extra time, by all means go with the membrane, especially if it is roller applied. Just don't use it myself......my 2 cents.