I set out to repair cracked grout at the top of a course of tiles on the wall immediately above my bathtub. After scraping out all the damaged grout I discovered that the only other thing holding the tiles in place was the caulking between them and the bathtub itself. I removed the tiles and found water-damaged drywall -- not cement board -- behind them. Each individual tile had been attached directly to the drywall with globs of a brown substance which I think is construction adhesive (it's definitely not mortar). The water damage caused the drywall paper to disintegrate, so the glue no longer had anything to hold them to.

Bathtub surrounded by tiled walls on three sides. The lowest course of tiles on one wall has been removed, revealing damaged drywall behind them. There is a soap holder glued to the tiles immediately above the removed strip. A boxy machine sits in the tub; this is a dehumidifier. Fig. 1 Bathtub with the lowest course of wall tiles removed, showing damaged drywall behind.

All of the rest of the grouting and caulking is in good condition, and the tiles one course up are still firmly attached to the wall; they don't wiggle at all when I push or pull on their bottom edge. I think this means the water damage doesn't extend upward from the crack very much.

After removing all of the ruined drywall paper, allowing the gypsum itself to dry out for 12 hours with a dehumidifier running full blast right next to the wall, and then lightly scrubbing the surface with a dry brush, it looks like the gypsum itself isn't completely ruined. It's cracked, chunks are missing at the bottom, and many of the nailheads are rusted out, but it seems to be fairly solid overall still.

Close-up of damaged drywall immediately after removing tiles and most of the drywall paper.  The gypsum is covered with some sort of brown deposit.  Scraps of drywall paper are visible. Fig. 2 Close-up of damaged drywall immediately after removing tiles and most of the drywall paper.

Another close-up of the same stretch of damaged drywall, after removing all the drywall paper, allowing the gypsum to dry out for 12 hours, and then brushing off the brown deposit.  The board is cracked and pitted especially near the bottom but might not be completely ruined. Fig. 3 The same stretch of damaged drywall after drying for 12 hours and then cleaning the surface.

I would normally call a professional for this, but my area is under COVID-19 quarantine and I don't want to make someone come to my house unless it's absolutely necessary. Also, I suspect a professional's idea of a proper fix would involve removing several more courses of tiles and possibly redoing the entire tub surround, which I cannot afford right now.

Online general advice for this sort of problem (e.g. this article) seems to be "cut out the damaged drywall, replace with cement board, tape and mud over the seam, re-set tiles with thinset and grout as normal." The problem with that idea is, the seam ought to go somewhere underneath the second course of tiles from the bottom. But I don't want to remove even one more course of tiles myself if I can avoid it, because that would involve removing the soap tray (which is probably glued to the tiles with more construction adhesive) and I don't think I can manage that without breaking either it or the tiles or both.

So, my question is, what is the most expedient way to repair this damage without removing any more tiles? I have two ideas myself, which I invite you to poke holes in:

  1. Given that the drywall isn't completely wrecked, just build the surface back up with thinset mortar applied directly to the gypsum, to the point where the tiles will be flush with their neighbors.

  2. Cut out the damaged drywall right at the bottom edge of the second course of tiles. Install a strip of cement board, but don't tape and mud over the seam between that and the remaining drywall. Do cover the exposed surface with mortar as thoroughly as possible.

I would prefer (1) because it doesn't involve going out and buying cement board (and having the store cut it for me, because I don't have the tools for that).

This only needs to be good for three to five years, because we're probably going to have the whole bathroom redone after that anyway.

The house was built in the 1930s; the bathroom was probably last redone in the 1970s. I bring this up because I suspect whatever's behind the drywall is not standard balloon-frame studs.

EDIT: I am fully aware that a "proper" fix would involve replacing considerably more of the wall. However, that is not an option under the circumstances.

  • 5
    How did your "top coarse" come to have all the other tiles above it ? Of coarse that would be the bottom coarse or the first coarse above the tub ? I am not trying to be coarse, i just like to point out the use of words as matter of coarse.
    – Alaska Man
    Apr 8, 2020 at 19:28
  • 3
    Cement board cuts with a utility knife just like drywall. Sure there is a special scoring tool for it so you can buy the tool (cheap) or you can just ruin a utility blade scoring it. Anyway, don't let "not having the tools" take away the better option.
    – JPhi1618
    Apr 9, 2020 at 18:46
  • 2
    @AlaskaMan If you take a closer look, what it actually says is "cracked grout at the top of a course of tiles on the wall immediately above my bathtub." The grout was at the top of a course of tiles - that course being the one immediately above the bathtub. Good snark, though.
    – Alex M
    Apr 9, 2020 at 20:56
  • 2
    At the bare minimum I'd remove one more line of tiles above the damage. You need to see how far the badness goes.
    – Criggie
    Apr 9, 2020 at 23:54
  • 2
    +1 for a well written, well documented, clear, concise problem statement that includes your current limitations and understanding of the fact that any answer that meets your immediate requirements will be sub-par as a long-term solution.
    – FreeMan
    Apr 14, 2020 at 16:39

20 Answers 20


Sorry, there is no shortcut here. It's likely damaged well beyond what you can see and the only fix is to tear that all out, remove the drywall that is likely crumbling, replace/repair any studs, check the bottom plate and subfloor for damage, and then restore the entire thing.

  • 1
    I am fully aware that a "proper" fix would involve replacing considerably more of the wall. However, that is not an option under the circumstances. Your answer is not helpful to me. I am only interested in answers that do not involve removing any more tiles from the wall.
    – zwol
    Apr 8, 2020 at 17:45
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    @zwol Any such option would only be a quick-fix, with the rest of the tiles coming down eventually. Let alone what health issues would be created.
    – Mast
    Apr 9, 2020 at 8:48
  • 14
    @zwol Then the answer is don't bother. You can't fix this without pulling out all of the drywall and replacing the tiles. Rotten walls don't care about COVID-19 - they require replacement whether it's convenient for you or not. It sounds like you know what needs to be done but that you're looking for someone to tell you that it's ok to just cover it with duct tape and it'll be fine - it won't. Presumably you have a lot of time to spend at home now - might as well make a project of it.
    – J...
    Apr 9, 2020 at 15:47
  • 1
    Drywall absorbs water and the water damage is at least 3-4 feet from where they entered, assuming the water came through the tiles from the bottom. The likelihood of this being true is next to none, so your entire drywall is basically gone at this point, with significant mold back there too. That's reality and there's just no "quick fix" for this.
    – Nelson
    Apr 10, 2020 at 14:28

With the COVID stuff going on the last thing you want to do is have your family have respiratory issues due to mold. There is mold growing behind your shower, probably on every shower wall. Money or time spent on patching this is both fruitless and reckless.

That article you linked to is click-bait nonsense - maybe 1 in 1000 showers have a little leak in one area where this would work. The site isn't helping you find a solution, the site is abusing SEO tactics to make you click on their articles.

Regarding you will be doing a renovation to this in 3-4 years. Doesn't matter. The tub/shower surround area is its own little island in a bathroom. You could easily update this and update vanity/toilet/walls/floor later with have zero impact on this. Also that tub in there is a great tub and will cost you a fortune to buy that quality now so the only thing you would do with that is a resurface.


  1. No way anything will stick to the leftover drywall remnants.
  2. By retiling here you are making a really bad situation worse. You don't have a good seam. You would have to take another row of tiles out and cut out and put in new drywall... but when you go a tile up that will be damaged too.
  3. You would be better off as a temporary fix taping some plastic covering over the area. At least you could pull the plastic up when done with shower to let things dry out.
  4. It is not expensive to tile your shower. You could put down 1/4"drywall + 1/4" hardiboard on top and some inexpensive porcelain for $200 in materials. I guarantee you could pull the tiles straight out of the wall using the mold-laden wet drywall. You could have it prepped in a couple hours. If you use something like redgard waterproofing you don't even need thinset and and it is a pretty simple install.

My Take: I am very familiar with this type of tile and install and going on drywall. I have demo'ed many many many bathrooms that look just like this. And the drywall is in like new shape. Honestly the amount of "waterproofing" we do these days for tub surrounds is kind of silly because if there is a problem you pretty much have to demo the area or whatever seam you use will be a weak point continually.

The 2nd picture is the most concerning. You have abundant and uniform mold growth. Meaning the other two walls have it too but also I have a feeling you can keep pulling tiles off and go up and you will see it uniform there too. It is really concerning because just eyeballing the shower I don't see any glaring grout or caulking issues - it looks pretty damn good actually. What does this mean? It means you have a persistent water issue that you have not resolved. If you want a cheap/temporary solution by a used shower kit (fiberglass insert) and surround your tiles. Or just big sheets of plastic and caulk the corners.

But you have some major mold and there is an unknown water issue.
You do not want to be inhaling mold and possibly be dealing with the current virus situation.

Note: Since the OP will not accept the actual correct answer and that is now a stipulation of their question. I will give a simple alternative to meet their needs.

For out of the box shower issues there is only one person I seek guidance from - The Karate Kid. His intuitive solution should hold you for a few months.

enter image description here

  • I am fully aware that a "proper" fix would involve replacing considerably more of the wall. However, that is not an option under the circumstances. Your answer is not helpful to me. I am only interested in answers that do not involve removing any more tiles from the wall.
    – zwol
    Apr 8, 2020 at 17:45
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    @zwol - we don't supply wrong answers on the site. I gave you a temporary solution that is safer and will work better. I am also looking out for you - so you do not get duped into putting in a lot of work that will waste your time and cause more problems. There is no way you are attaching anything to that drywall correctly.
    – DMoore
    Apr 8, 2020 at 17:56
  • 7
    @JD - That is one crazy comment. Spackle does take to drywall but not water rotted mold infested drywall. It certainly won't "strengthen it". The spackle will mold and it will leach into shower area and the mold will cause the "new" tiles to pop off. And I should have said "we don't supply wrong answers on the site on purpose". Just like your comment, I think if you would actually go through this process in your own home I doubt you would be telling others to do it.
    – DMoore
    Apr 9, 2020 at 15:46
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    @JD - you can get rid of mold on drywall? Damn I have trouble erasing mold from under shampoo bottles in my kids bathroom. I would keep whatever secrets you have to yourself about this mold abatement and start a business. There are dozens of multimillion dollar businesses that do abatement that have never figured out how to get mold out of gypsum but I guess you have the secret.
    – DMoore
    Apr 9, 2020 at 16:11
  • 1
    I agree this needs a permanent fix, but there are certainly grouts and cements that will adhere to a damaged drywall. There are also porous fibre tapes you can use with cement to ensure a good bond and support for tiling. Mold is an issue, but it is not an immediate killer and you can wait a few months.
    – Stian
    Apr 10, 2020 at 11:17

You say you're looking for an expedient fix for the duration of the lockdown? That's pretty simple then. Buy a cheap shower curtain, cut it roughly to the size of the missing tiles, and Duck-tape it over that area. Duck tape (the brand) will comfortably stay waterproof for a few months; other brands could well be equally good.

If you plan to renovate the wall properly later, when finances and virus are both sorted, then there is no reason to over-complicate a fix which will get you through for the moment. I've done this myself in a rented house whilst waiting for the landlord to (eventually) call a tiler. It might not be 100% attractive, but it'll see you right for a while. And if that's the most aggravating part of your lockdown, you've not done too badly. ;-)

  • 1
    I would add that I would not duck tape the bottom. I am kind of doubting the duck tape will keep underneath completely dry and if you tape the bottom you are basically creating a steam bath for the mold walls. But certainly duck taping the top area and flipping up the shower curtain 1 hour after shower to dry everything up is pretty doable in short-term.
    – DMoore
    Apr 10, 2020 at 21:16
  • @DMoore If you don't then water will tend to splash up there, and more steam too, and it'll all go bad very quickly. It's all going to be fixed properly in a while anyway, right? Oh, and top tip for a good seal with duck tape - lay down a run of tape on the surface you're taping to, get that good and secure, and then stick your duck tape with the shower curtain to the first lot. The first run gets a better stick, and then the tape likes sticking to itself so the second lot holds better.
    – Graham
    Apr 10, 2020 at 22:41

First off, Don't use thinset on drywall. Use a mastic adhesive because it will be better for the damaged area. After the tiles have been installed, use an epoxy grout for maximum strength. Seal around the tub with a quality silicone caulk.

Note: This would not be a normal recommended repair from me but since you stated some parameters, I tried to stick to them. Good luck.


Hang another shower curtain on the back wall with a tension-rod. That will let it continue to dry out and should be cost-effective until you can take it down to the studs and see whether the wood needs to be repaired.


I side against those who say retiling the wall is the ONLY way to do this. Nonsense. My quickfix is similar to graham's, but I think a little more durable since even joint mud is generally very absorbant!

Now you say the visible drywall is decent shape and not rotted out. If that's so, what you want to do is spray down the lip of the exposed drywall lightly with bleach to kill what you can. Gypsum is alkaline so don't use acid. After that dries out thoroughly (open a window for God's sake, and use a fan/blower if you can manage), what you want to use is spackle, because unlike mud, it has glue in it and dries much harder than joint compound. You probably can get away with a 2" knife for application. Really do your best to get it level, preferably below the drywall surface above, because the stuff is tough to sand. Again, dry it out throughly, and apply a second coat because the stuff tends to shrink. Once, the second coat is dry, if you have an oscillating tool with a sandpaper attachment, try to get it as level as possible. If you happen to have a little oil-based primer lying around, great! Hit it with a coat or two for waterproofing, but I wouldn't sweat it if this is a temporary fix. When it's all dry, you're ready to take a tube of construction adhesive, or in a pinch some binary epoxy (I'm assuming you've cleaned the back of the tiles off with a scraper), and put the suckers on. Then grout and wash. Then lastly your standard bathroom/kitchen silicone caulk.

Let's see what you've accomplished:

  1. You've preserved the existing wallboard and its backing preserving strength across the seam between the first and second course of tiles. Cutting out what is there would not do so.
  2. You've releveled the material and strengthened it with a glue-impregnated gypsum matching the original board's composition. With elbow grease, you should have a relatively level surface.
  3. If you have the oil-based material, you now have a water barrier at the bottom of the wall where water is most likely to accumulate.
  4. If you use a good adhesive, your tiles are secure to the wall.
  5. If you grout and caulk and your tiles are in good shape, then you have a waterproof barrier on top of the surface all of which would probably outlast the original installation technique.
  6. You can adjust the method to match your skills/abilities/cares/materials.

Replacing the whole shebang is just nonsense, and the notion that no bad answers are given on this site is equally silly.

Good luck!

  • Addendum: After my back and forth with dmoore, it did occur to me if you have some paper or fiberglass mesh tape handy, you could also make up for the loss of the paperboard on top.
    – J D
    Apr 9, 2020 at 15:57

You just want to fix it for the shorter term which makes sense to me. Remove the old dry wall and replace with a piece of 1/2" sheathing making sure that the ends are supported so the tile won't crack there later. Then glue on the tile. This will hold you over as you desire but is not a true fix or longer term solution.

  • 1
    My guess is it isn't the OP but someone who doesn't think anything will stick to that drywall... If I DV, I explain +.
    – JACK
    Apr 8, 2020 at 18:33
  • 5
    I agree none of these will be permanent solutions or "doing it right." But short of ripping the whole thing down and "doing it right," if it holds for 6-12 months, doesn't damage the wall behind too much (is mostly waterproof) and we're not going to enter these solutions in Fine Homebuilding, these would probably work for long enough to use the bathroom for a few years. Perfection is the enemy of good enough. This won't be the worst thing anyone has ever done in construction. (Garden hose for plumbing wins that one....)
    – VWFeature
    Apr 9, 2020 at 0:49
  • 1
    I have done this a few times and it has held up well . Last one was 3 years ago and I recently was called back for another repair. The shower is used every day and it still looks fine.
    – Kris
    Apr 10, 2020 at 14:23

Tile over drywall was very common in the 50’s-70’s and is still done today for quick cheap flips. The best way would be to replace the entire wall as matching the grout usually shows a repair, I have saved expensive tile and in my early years on my own homes I saved even cheap tile. One trick if you break a tile or 2 is to make an accent stripe with a complementary tile different color, or painted flower I have even staggered them when I had trouble with breakage and it provided an updated look.

You can just repair the minimum as some do but you will probably have to revisit for additional repairs in the future or that is what I have seen in the past.


Cut out the plasterboard that can see and fill with sand and cement them tile it will do for couple years but will not be permanent fic

  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know the details of contributing here. Apr 9, 2020 at 13:56

Cut one more course of tiles out. If plasterboard wall still good install 6mm Fibre cement wall as backing prior to tiling.

  • Thanks for the answer, and welcome to Home Improvement!
    – IronEagle
    Apr 10, 2020 at 1:42

First completely clean all chaulk residue and any other debris, then use a quick set drywall mud like 30 or 45 type ,mud area completely make sure to fill all cracks and holes completely let it dry thoroughly then apply your mastic, set your tile ,grout it and chaulk it as needed let it dry completely before you get it wet about 48 hours I not sure how long it will work but I think it is the fastest way to solve your problem other than a complete redo good luck also you might need some mesh tape for added support with the drywall mud


I would remove most of the loose stuff, then repair with the best water-resistant wall patching compound you can find. Regular drywall mud generally isn't too water-resistant, so look around at the other options.

After patching, you may consider soaking the patch with some sort of water sealer. Then attach the tile with a non-water-based adhesive.


This is a method that I have used to good effect when installing my own showers. My first install was done 13 years ago and is still watertight. It keeps the drywall (plasterboard) dry behind. Get an aluminium strip (I use 1.5mm sheet) cut to the length and most of the height of the tiles you've removed. Silicone the strip in place and where there are studs behind the plasterboard, you can screw the strip to the studs to get it really firm. Make sure the bottom of the strip is tight against the bath and there is silicone in the joint. Smooth off any excess.

Then once the silicone has gone off, re-affix the bottom course of tiles with more silicone. Use tile spacers etc as if you were using tile cement.

The silicone will keep the water out for good. You could view it as a temporary fix that will last 5-10 years.


I had the same exact problem like 7 years agi. I had a tile guy come in and he cemented them back ( I can not remember if he used the same backer board and put new one some how). He said it is temporary fix. But, importantly, I had tile refinishing people and spray low voc epoxy on the tile (it's called refinishing I think) and 7 years later the shower is still going strong with no leaks. I highly recommend tile refinishing for old shower tiles. (Mine are 40 years old). It does buy you time till you get the $$$$ to re tile!


Install a strip of white PVC (Home Depot) caulk it completely with clear bathroom silicone, wait your five years and then redo the entire bath. Make sure you have no more water leak. If your really finicky the PVC can be spray painted to somewhat match your tiles. Cheap, fast and it won’t really look that bad!


Cut old stuff out put in new concrete board piece and paint with a water proffer. let dry 24 hrs get some mastic if you can not mix up some mud replace tiles. you can cut with a grinder wheel for tile don't need a wet saw for a few pieces. install let dry till next day get some polyurethane grout and some tub and surround chalking grout let it and chalk let dry and you will fine. You can get all this at Lowe's or home depot


Just cut out the damaged board replace it with a piece of aqua board stick tile to it scrap out old grout on the above tile regrout the 2 tiles job done


I had the same issue in my shower in a rental house in about 1975. I got the advice of a wise old man at a home improvement store, and followed it. This could be considered a permanent repair -- at least it lasted for many years. (I moved out of that place for a few years, then moved back in, and the repair lasted until 1991 at least, when I moved out again.)

  1. Pack the void with steel wool.

  2. Use Liquid Nails or some other construction adhesive to hold the steel wool together, and install the tiles on top of it, using the construction adhesive to hold the tiles in place.

  3. Use a piece of wood as a press to ensure that the tiles are even, and grout between them.

Surprisingly, this cheap repair looked just the same as the undamaged tile. Since it was not my property and I was a poor graduate student, I did not want to spend much money.

  • Thanks for the answer, and welcome to Home Improvement!
    – IronEagle
    Apr 10, 2020 at 17:50

This pertains mostly to removing moisture.

I live in an apartment in which the landlord does no repairs. (no minor repairs; if it's a big deal he rushes over and fixes/has it fixed) He's a twenty something kid that inherited the place and many others from his grandmother. But since the rent is absurdly cheap (half of surrounding rentals), I don't sweat him for this. I have lived in his/grandmother's property for years now because of the informality and low rent.

At any rate, this has caused me to learn a lot and get creative. As in, how does one replace an entire wall without replacing the wall? Honestly, there's some great answers above. The steel wool method being the best. If the grout is done properly, the notion of 'water leaking in in the future' is moot. Replacing the whole wall being the only correct way is nonsense. That's something the repair guy tells you to charge you more money. Period.

About 2 years ago, I had a little disaster while making nitric acid in the bathroom (don't ask). The reaction ran out of control, leaked out of the reaction vessel, ran down the wall under the window and onto the floor. Talk about a mess. I neutralized the spill as quickly as I could but the damage was done. I couldn't do it right away though. I had to wait until the fumes cleared. If you've ever had the sheer joy of getting a lung full of nitrogen dioxide, you know what I mean. The floor is covered by 12" tiles, old fashioned style. The grout was eaten, the tiles loosened and the wood underneath eaten a bit as well. How could I tell the landlord about this?

tl;dr (I ramble a lot) bathroom floor and tiles badly damaged by nitric acid.

Liquid nails is your friend. There's some even better stuff that you never hear about. It's an adhesive used to attach solid surface (acrylic countertops) to substrate. It's a two part adhesive that comes in a 2 section caulk-like tube in which a mixing tip screws to the top. The brand I used is called Integra. I got mine from my work but I think it's a little expensive, around $20. If there's no ventilation in the bathroom, you may not want to try it though.

I often joke that some future civilization 2000 years from now will find those bathroom tiles attached to wood-turned-plastic and wonder what they are. The landlord sure as heck won't be able to pry them up. Serves him right imo. When I walk on those tiles now, it feels like solid concrete. In that bottom picture, the drywall looks decent. Keep drying it for another day.

As a chemist, here's a neat trick to dry. Put Epsom salt on a cookie sheet in an even layer no deeper than 1/4". Put in the oven at 300 degrees (Fahrenheit) for awhile, mixing often. Weather permitting, leave the oven door open a crack to speed up the process. It's 'done' when it looks white and flakey instead of like crystals. You have now turned Epsom salts, MgSO4+7H2O into MgSO4 (sort of). A great drying agent that is relatively safe. As in, you can touch it and whatnot, just wash your hands after. You could use sodium hydroxide (in case you see this online somewhere) but it's not safe at all. It's corrosive, burns your skin, and if you get even a tiny speck in your eye, your eye will be gone and most likely need to be removed from your head. Don't use it.

Put your new drying agent in a panty hose type stocking in a shape that fits in that crack. Leave it there over night. Examine the drying agent and if looks like Epsom salts again, repeat the process. (you can reuse the drying agent by putting back in the oven) Then continue in one of the methods of your choice. Use silicone. Seal the crack completely. Replace tiles. Grout properly. Remove any old grout first. Seal around tub with silicone. Home Depot sells single tiles (where I live anyway)for cheap so if you break one, don't sweat it.


Black mould is still very present on the drywall from what we can see on the "after" pictures. I have refinished bathtubs and replaced tiles for over 10 years. My experience tells me that if you have mould you cannot clean it on the surface. Secondly you surely have more mould elsewhere around the tub. I tried to fix a few but soon realized that this "plaster" sollution was not the way to go. Any time I had such a situation I would refuse to take on the work if a complete fix was not undertaken. "Inhaling mould fragments or spores can inflame the airways, causing nasal congestion, wheezing, chest tightness, coughing and throat irritation. Prolonged exposure to high levels of indoor dampness can reduce lung function and cause chronic health problems such as asthma.Nov 1, 2015"

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