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Repairing Bathroom Plaster for Tiling

Posted by cluelesshomerepairer (My Page) on
Sat, Aug 3, 13 at 0:55


I have a section of tiles and plaster fall off in the middle of bathroom bathtub area where the shower often sprays at. I've read through dozens of threads here, and am still unsure on the best thing to do, so I would like advice and confirmation. I have no experience what-so-ever with home repair.

In the picture of the damage, it looks like to me, from the back to the front: metal barbed wiring, some wood-like substance (lath?) plaster (the gray stuff), mortar (white stuff), and then the tiles.

Here's the procedure what I think should be done:
1. Clean out the area by removing loose tiles, mortar, and plaster by hitting it with a screwdriver by hand. Spray the area with water until it's almost dripping wet.
2. Apply SHEETROCK Brand Durabond 90. How many applications? What's the thickness of each application? How long should I wait between applications?
3. Apply a mortar. Is there a specific one I should get? What properties should it have? Something for use in wet areas, and to bond with Durabond?
4. Tile, grout, seal. (Don't know how to do any of that yet.)

Thank you for any advice!

Follow-Up Postings:

RE: Repairing Bathroom Plaster for Tiling

Plaster isn't waterproof. Tile isn't waterproof. And you've been spraying it with water. You have a failing system here. All of the walls around the bath need to be replaced entirely. As in a gut remodel of the plumbing as well. Or restrict yourself to only tub baths until such time as you can replace the entire structure.

RE: Repairing Bathroom Plaster for Tiling

Thank you for your posting!

I understand that plaster, mortar, and tile is not waterproof, but that's how my the bathroom is. However, based on reading other posting on this forum, it seems that some plaster is waterproof (Durabond?), while some are not (Plaster of Paris).

I don't have the money to redo the bathroom right now. I'm looking for a fix for maybe two years until we can afford remodeling it. I don't think I can replace it with a cement board myself.

RE: Repairing Bathroom Plaster for Tiling

you can try to patch it up, but it needs to be gutted and redone correctly with cement board, not plaster or sheet rock.. You never tile on an area that isn't water proof..

You can patch it, it's only a temp bandaid on a big problem... You are very likely getting rot in your walls, framing... not to mention mold... mold can be deadly

RE: Repairing Bathroom Plaster for Tiling

That is put a shower curtain against the wall until such time as you can gut the whole thing. That's not really "spot repairable". And yes, you're going to find some water damage to the wood behind those walls. More if you try to repair it and don't cover the whole thing with the shower curtain and don't allow it to get wet.

Read up on how to construct a waterproof tub/shower. It's not that hard, and if you've got a long weekend on Labor Day, you can probably get it done then for not much more than buying all of the materials that it would take to patch it. As long as the water damage behind the wall is minimal, that is. A couple of sheets of cement board, some basic tile, a new shower valve and control, and 4 days to be sure you have enough time. It's doable for under $200 probably if you keep the tub.

RE: Repairing Bathroom Plaster for Tiling

There's a much faster/cheaper way to cover this up, that we GW-ers often forget: put an acrylic or fiberglass surround over top of the tile. That'll seal it up just fine and look decent until clueless can redo the tile.

BTW, I'm a DIY-er with decent skills and I couldn't demo a tub and put up new tile all in one weekend.

RE: Repairing Bathroom Plaster for Tiling

Cement board isn't waterproof, either. You need waterproofing either behind the cement board or on top of it. I wouldn't put a surround up without tearing down the tile, though. There is sure to be mold there. You can put up drywall and then a cheap (I think i'ts about $50-$75) surround.

RE: Repairing Bathroom Plaster for Tiling

We're only talking a tub surround here, not an entire bathroom. 50 square feet. Tops.

Day1. Demo existing. Put some plywood over the tub to protect it, and get out your sledge hammer, sawzall, and multi tool. Assess the water damage. If it's only mildly water damaged and the wood is still solid, just spray with some hydrogen peroxide and let dry, If there's more damage, it will throw the timing off, but you'll be glad you tackled this sooner rather than later.

Day 2. Sister some studs to the existing to bring the level of them forward to account for the lathe and mud bed that you just demo'd. That's the hardest part of the whole job, so I'm giving the whole day to it. Install some insulation into the cavity and put up 6 mil poly stapled to the studs and overlapping the tile flange of the tub.

Day 3. Apply cement board and tile with basic 4x4 tile. As long as you're not doing a fancy pattern or even worrying about the edges (use a Schluter strip for them) 50 square feet will go fast. That is, if you did a good job on Day 2 making the walls straight. The tile already has lugs on it for proper spacing. You only need to cut a few, and you can borrow a tile saw from a friend or rent one. Again, if you made the walls straight the cuts should be nice and straight without having to worry about wavy walls.

Day 4. Grout and let installation cure.

Take a bath until the next weekend when you can seal the grout.

RE: Repairing Bathroom Plaster for Tiling

Thank you for your responses! I'm not up to redoing all the walls, even just around the tub. Remember that I have no experience at all.

Can anyone confirm that's actually lath and plaster? It doesn't look the same as pictures on the Internet. Also, there's a metal mesh behind the wood-like substance. Perhaps it's cement?

If it helps, I live in an apartment building built in 1963.

RE: Repairing Bathroom Plaster for Tiling

Holly: I'm somewhat bemused to be arguing with you on how long it takes to redo a bath, because I'm usually the one saying "no way that contractor should take a month to remodel your bathroom; it should be 1 week tops!"

But I just finished tiling a tub surround with subways and it took 2 full Saturdays for tiling only. Granted, that included a window and a niche, and a glass listello, but there are still plenty of cuts on ends/corners.

You also neglected the paint-on waterproofing over the cement board, which needs a day to dry, though you do have the plastic moisture barrier, so that could be omitted.

You also forgot the 14 trips to Home Depot for the stuff you forgot to buy or didn't get enough of. Or the new stuff you need because you encountered something unexpected.

Oh, and my weekends are only 2 days long. :-)

In any case, we're hijacking the poor OP's thread. Sorry about that, clueless.

Our 1920 house has lathe and plaster walls but the outside walls all have boards with grooves routered into them for the plaster keys to hold to. Does it look something like this?
 photo 101_2357_zps16bfb8ce.jpg

Also, the wire mesh is used in an older method of tiling, that entails embedding the mesh in concrete, making a pretty thick and incredibly stable wall. However, it's done in lieu of plaster, not behind it, so I'm not sure why it's there in your situation.

Bill V could probably tell you how/why it was constructed that way, though I haven't seen him around for a while. You might also try posting in the Old House forum for someone who might be able to explain the construction.

What everyone else has said is correct, however: you need to not just put plaster and tile back here. You either need to cover it up short term with something that will protect it from further damage, like a sheet of acrylic or fiberglass surround, or else rip it out and repair it. You could also just rip the whole thing out and put in an acrylic/fiberglass surround for a few hundred bucks and some elbow grease.

RE: Repairing Bathroom Plaster for Tiling

Thank you weedyacres! My spouse would like to retile the entire bathroom in a year, so I expect to take the whole thing down and redo it correctly then. Probably not myself, as it's our only bathroom. I'm starting to think it's actually concrete rather than plaster, based on your comments. I will get some supplies (brushes, etc) to clean up the area, and maybe I'll have a better idea of what it looks like.

If it is indeed concrete, would it be possible to just patch the concrete then? (using joint compound, such as durabond?). I understand there are waterproof concrete. It's only a 2x2' area. If it lasted 50 years already, why is it a problem now? I really prefer not to rip the whole thing out.

RE: Repairing Bathroom Plaster for Tiling

Hello Experts, In the attached pic, you can see two columns of tiles in my bathroom are protruding outside. I am afraid when I take shower water gets inside the tiles and make them worse.
I live in this rented apartment and I need to live here for next 3 months only ! Any suggestions on how to fix this are welcome. Also there is dirt on the tile walls. When i try to scrub off the dirt, the plaster also peels off. I got a DAP Patching Plaster yesterday from Lowes thinking I can use it to mix and apply. Pls. suggest how to fix them. Thanks.

RE: Repairing Bathroom Plaster for Tiling

I see you just registered, so welcome. However, one of the basic rules of these forums is that you don't hijack someone else's thread with your own issue. Start your own's politer and you'll be more likely to get your own issue addressed.

RE: Repairing Bathroom Plaster for Tiling

OK, as I understand it, you want just to fix the problem t hand, and everyone here wants you to invest in a complete redo.

Here's what I would do to fix just the problem at hand:

Use 1/2 Durock brand backerboard to fill the hole and built out the wall to the level of the existing plaster. Durock is very resistant to water damage, and can even be used outside.

I would clean off as much of the old plaster as I can from the wood lath so the Durock lays flat.. Some of the lath may be rotten, but don't worry about that. Replacing the lath is something you do when you rebuild the entire tub surround.

If the old plaster is thicker than 1/2" you may have to shim the Durock. If it is over 3/4" thick, use a 1/4" plywood board behind the Durock for more strength.

Then set the eilin thinset mortar, adjusting the thickness of the mortar bed so the relayed tile is even with the surface of the existing tile. Easy, peezy.

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