Some tiles in shower bend when push on wall

[Betsy Callahan]

Master bath shower in home built in 1989 has 4 1/4" x 4 1/4" white, shiny tile on 2 walls with glass enclosure making the other 2 walls of enclosed shower. I noticed some grout was failing and if I gently push on some areas of the tile, those areas bend inwards, and in other areas it does not bend at all. Does this sound like a problem with the wall that the tile is cemented onto or would loose, old grout cause this to happen? I was going to clean out the grout and re grout the tile, but if there is a problem behind the tile with the wall itself, I need to fix that right? I haven't taken a shower in that shower since I noticed this, because I don't want water to get through the grout and back into the wall. Any insights as to what may be happening and what to do are greatly appreciated. Thank you.

 

[wwhitney]

Some semi-informed speculation:

Waterproofing standards for showers in 1989 were poor. Your shower could be just tiles directly applied to "moisture-resistant" gypsum board. That system relies on the tile and grout to send most of the water down to the drain; some water seeps through the grout and tiles to the gypsum board and over time weakens the gypsum board. Which would explain the flexibility you see when pushing on the tile. Missing grout accelerates this whole process dramatically.

Modern practice is to have an explicit waterproofing layer between the tile and the framing, and no gypsum board on the wet side of the waterproofing layer. So the long term solution is to rebuild your shower to modern standards, which means taking it down to bare studs. A short term band-aid solution is to patch your missing grout and hope that it lasts another year or two. And further hope that whatever hidden structural damage there may be doesn't progress in the meantime.

Cheers, Wayne

 

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[Jadnashua]

I think that Wayne hit the nail on its head...sorry.

A properly built shower should not be damaged even prior to the installation of the tile and grout. Tile doesn't like movement, and if things behind got wet, they tend to swell up. It doesn't take much movement to crack grout which is usually weaker than the tile itself. Now, those small tile are likely bisque, and fairly soft rather than the more common (today) porcelain tiles which are much stronger.

 

[Betsy Callahan]

Thank you Wayne and Jim,

I scraped the grout and 5 tiles came off pretty easily. Wayne was right, there was wet dry wall or gypsum board that broke up and peeled off really easily and the insulation in the wall between the studs was slightly wet also. I did not see evidence of mold or any rotting of the wood stud that the drywall was screwed into. There is a continuos area of about 12-15 tiles that are moveable and the rest of the shower wall is solid. If I removed all those bad tiles and wet drywall (or whatever it is) and cut a new piece of material to re grout the tiles to and fastened it to the studs and grout sealed the grout in the tiles that don't move, would that let me use the shower again? What new type of waterproof drywall should I use? I saw some, "GP toughrock mold guard" type of drywall at Home depot that I could probably cut to size and screw to the studs after I cleaned the old stuff out. Would that work? Also what is the best water proof grout sealer? There are several types of grout sealer at Home depot that vary widely in price. Some just say they are stain resistant, but that doesn't mean water proof right? Any advice is appreciated. Thank you.

 

[wwhitney]

It's impressive that a shower constructed like yours has lasted 30 years. Your dry climate has surely helped with that. You aren't going to get another 30 years out of your shower. You could do a band-aid repair and hope to get 1-5 years out of it. So the question is whether you want to replace the whole shower now or in 1-5 years. I would recommend replacement now.

When the tiles came off pretty easily, where there small areas of hard porous material stuck to the backside of the tile? Or was it just a gooey material you can scrape off? The latter would be mastic, a tile setting material not really suitable for a shower, and another strike against your current construction.

For a short-term repair, you'd remove all the wet drywall you can until you have an area where all the boundaries are sound. Then expand the opening left and right to the next studs, and preferably up and down to be rectangular. At the studs, rather that going to the middle, it may be easier/wiser to remove drywall just to the edge of the studs, and add some blocking alongside each stud to fasten your patch to.

For the patch you want a waterproof non-drywall tile backer that is of a thickness matching the drywall. Simplest would be be a foam board like KerdiBoard or GoBoard. The fastener locations need sealing per the manufacturer's instructions, and you really should attempt to seal the patch to the adjoining drywall, which I'm not sure how to do well. Then you can patch in your tile (avoiding mastic, the setting products in a bucket). As to sealing the grout, I don't really know if that will help.

Cheers, Wayne

 

[DIYorBust]

It couldn't hurt to seal the grout in the rest of the shower. I think applying over lime plaster probably would work, certainly over a thickset surface would work, so it seems there was a period where people decided it was okay to put tile on sheetrock. Now on the other hand, I have a 2 showers like this. One I recently retiled and the sheetrock was in 100% fine condition when I did the demo. I did replace it with cement board, and a kerdi liner. The kerdi can go directly over sheetrock. Another newer alternative is fiberglass backed drywall, although it makes me nervous as a tile backer.

For the patch, what I would do is cut a piece of cement board, and patch it in, tile over that, and seal the grout. Showers made this way more or less hold up okay, although a fully waterproofed shower is clearly better. Now you could waterproof the heck out of that patch, use a kerdiboard etc. But should you? Well where's that water going to go? That's right, into the surrounding sheetrock. With the bare cement board, it will probably absorb in a bit and dry to the other side. One thing I do like to do is put a little redguard on the stud or whatever you're screwing the cement board into. It definitely doesn't help to have the wood getting wet.

Edit: One thing I forgot to ask. Do you have matching tile, or will you be counting 100% on reinstalling the old tiles?

 

[Jadnashua]

Today, the industry guidelines prohibit the use of any drywall board in a wet area except for a couple of very specific situations (where a waterproof membrane is applied - there are only two that have the proper certifications). Cement board is not waterproof, but is not damaged by being wetted. The industry guidelines call for a moisture barrier (not waterproofing) to be either on top of the wallboard, or behind it, to protect the framing. That waterproofing should drain towards the inside of the shower pan, or if in a tub/shower, inside of the tiling flange.

So, while a tearout is probably called for, the best fix to keep it would be to staple up some plastic sheet or roofing felt on the studs, bring it down low enough to lap over the tub's tiling flange, then use some cement board. Note, not all of the so-called 1/2" cement boards are actually 1/2" thick, so verify, as to match up with the thickness of the existing drywall, you'd want one that was (for example, HardieBacker is 7/16" thick, not 1/2").

Don't use mastic, use a thinset that you buy in a bag and mix with water. Generally, that comes in 50# bags, but some places sell it in smaller boxes for repair. You need to check the date code, as you don't want it if the box or bag has a tear or hole in it, or it is older than a year.

FWIW, a tile/grout sealer doesn't really stop moisture penetration. When first applied, it might for a bit, but it is designed to make cleanup easier, not to prevent moisture or crud from penetrating...it's to slow it down so you can clean it up before that happens.

 

[Betsy Callahan]

Thank you all very much for responding. We plan to be in this house probably 2 - 2 1/2 more years tops. DIY, I was planning on using the same tiles, just because I wanted them to match the other tiles in the shower. I found 4.25" x 4.25" white tiles at Home Depot, but it didn't look like they had the same outer shiny ?porcelain sheen on the surface like the ones in my shower do. There are tile stores in town, should I try them? I think the tiles are porcelain, but I am not 100% sure. I measured the thickness of the current ?drywall and it is just short of 1/2". Wayne, on the back of the tiles I took out is a dried thin layer of a flaky, whitish grey, clay like substance that flakes/scrapes off, and on all of the tiles, lots of the wet cardboard/thick brown serrated paper layer that makes up the outer part of the ?drywall is stuck to the back of the tiles on top of this grey substance. Also I can see that the 2 screws that screwed the drywall into the studs are badly rusted and 1 of them has a small part of it's head missing. If I can buy exact matching tiles I will do that, instead of trying to clean off the back of the current tiles. It looks like a lot of work to perfectly clean off the back of the old tiles, and I want them to sit flush if I re-tile. Is there a product I could use to do that if I can't find matching tiles? The ones I saw at Home Depot were inexpensive. I was thinking of sealing the grout in the rest of the shower just so water wouldn't leak through it and give me the same problem I have now, in the rest of the shower. If over lime plaster is better I will use that, I have never heard of that. Just out of curiosity, how much ( ball park ) do you think a tear out/professional shower remodel would cost? I am going to remove the rest of the loose tiles now and see how big a problem area I really have. Thanks again all of you for your insight.

 

[DIYorBust]

You will probably not be able to match the tile perfectly with new tile, but if it's a standard size, you can try to find something you can live with. Use one of the methods described to make a patch, and then use mediumset mortar such as prolite that can be built up more than thinset. That way you can build it up if your backer isn't flush with the sheetrock. There is a pretty high risk of breaking the tiles when you remove them so factor that in to your plan. You need a tool to remove the grout around the tile, then try to separate the tile from the sheetrock and/or cut the section out depending on your judgment. With similar tile but not perfect matched tile, you may do better redoing one wall worth of tile, but it is hard to say without seeing it. Lime plaster is not something you would install in this situation.

Now to demo and retire the shower would really depend. Can you do just the shower, or do you need to redo all the tile in the room? Is there other plumbing or structural work needed? How big is the bathroom? I could easily see this project going to 5-10k. If the shower alone can be retiled, maybe less. But given what we know so far, it sounds like a slippery slope of expensive work.

 

[wwhitney]

Please be aware that if you sell the house before fixing the shower, you'll be required to disclose the problems with the shower to potential buyers. I don't know what the real estate market is like in Phoenix, but it is certainly possible that the cost to fix the shower would be recouped in the sale. In which case if you can afford to fix it properly now, you'll get to enjoy the new shower during your remaining time in the house, at little or no net cost to you in the end.

Cheers, Wayne

 

[Betsy Callahan]

Thank you all for your insights. What a difference a day makes. The ?sheet rock or drywall was nailed to the studs NOT screwed in and the nails are so rusty that the heads break off when you try to remove them. On one of the vertical studs they added a ?particle board shim part of the way up the stud vertically. Does that mean they measured wrong? The wet drywall crumbles apart very easy, but the tiles that are attached to the dry, normal drywall are very difficult to remove and I already broke 1 of the tiles trying to remove it. You were right DIY. I have my husband's Dremmel oscillating tool with lots of attachments, but where the water did no damage, it is very difficult to remove any tile. The drywall and the tile in those areas are very firmly attached to each other. It looks like it is almost all of the the lower half of one wall where the problem is, and the rest of the tiles and other part of the wall seem to be fine. I would like the tiles to match, how do I clean off the stuck on dried brown paper and clay like substance ( ?mastic ) on the back of the tiles? Should I try to scrape it off with a razor blade or sand it off with the Dremmel tool sand paper attachment or is there a chemical product I can use that won't damage the tile? I have some goo gone, will goo gone make the tile less water resistant? It says it has petroleum distillates in it. Is cement board sold at Home Depot or Lowes? The Dremmel tool has a dry wall cutting saw attachment, will that cut cement board? I would have to give any future buyer of my home a generous allowance for bathroom remodels, the bathrooms are pretty dated and look that way. I don't have a problem telling the truth to a future buyer, I just want my master shower working again. Thanks again all for your insights.

 

[wwhitney]

If it's really mastic, soaking the tile in a bucket of water for a while should turn it gooey. If it's a cementitious thinset you'll probably have to mechanically remove it.

Is the area with the damage somewhere that gets extra water? E.g. the lower half of the wall opposite the showerhead?

The box stores carry cement board, but a foam board is easier to work with. Cement board dust has silica in it, so it's best to try to cut it by scoring with a carbide knife and snapping, although I don't know how well that works.

Cheers, Wayne

 

[Jadnashua]

CBU is generally snapped rather than cut. THey sell a special tool to score it that isn't expensive. Note, when you snap it, you snap towards the score, not away from it which seems counter-intuitive. Some cuts easier than others. Most home centers will have at least a few brands of cement board and the special screws used to attach it to the studs.

It will be a pain if they used a cement based product, but mastic, as said, may just re-emulsify if you put it in a bucket of water. If it does, it will get soft and you can try to scrape it off. Cement won't get soft if it gets wet. Depending on how much is really there, the least expensive would be to try a rubbing block. If that takes forever, a diamond cup wheel on a grinder would remove it fairly quickly, but will be dusty.

Tiling directly to drywall is done all of the time in DRY areas, and it holds quite well. It hasn't been approved for use in wet areas for eons, though, and never was a great idea.

 

[DIYorBust]

Can you post a picture of the project?