Is a small hole in the bath tub wall tile grout cause for concern?

[JasonM]

I have about 40 years old bathtub wall tiles with grout in between. The tile size is about 4 x 4 and grout is about 1/8 to 3/16" thick. It is old, and sometimes due to the wear from the cleaning chemical like diluted CLR, I see a very small holes here and there in the grout.

Is this a cause for concern because water seeping thru the hole behind the tiles can lead to mold or termites damages later on? Or is the back of the tiles and grout sealed so that the moisture can not reach the stud in the back? I am going to repair later on, not right away, though.

Thank you.

 

[Jadnashua]

FWIW, neither tile nor grout are waterproof. A small hole should not be a major concern IF the whole thing was built well. No guarantees on that. CLR might be a bit strong if you don't rinse it off well. While it has more than a few components, one of them is a mild acid which can dissolve the cement.

What doesn't run down the wall and gets into that small hole should evaporate between uses. Even if it were in a shower on the floor, any moisture that got through below, SHOULD drain out the weep holes. Again, that assumes it is build according to industry standards.

Should you ever decide to regrout, you need to cut out at least 1/2 of the depth so that the grout has something on the edges to grip to. On smaller tile, that can be tedious, but it does work. Industry standards call for the changes of plane and materials have a soft expansion joint. Most of the time, that ends up a grout color-matched caulk. Those areas tend to crack through movement between the different surfaces over time (and sometimes, not all that long!).

 

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[JasonM]

Thank you jadnashua very much for the comments.

In the past after I cleaned the bathtub wall regularly with diluted CLR, I noticed that the grouts were worn down, looking porous a little. So, I clean less with CLR these days.

Can I ask some more questions on this?
1. Right underneath the tile and grout, there is some kind of cement mortar so that any kind of wood like stud is not in direct contact with any water coming from the tiny hole in the grout. Is this correct?
2. I learned a new word, weep hole. Thank you. I looked up for the bathtub, and I did not see any slit near the surround of the bathtub looking like the weep hole. Was it the standard for a house built in 1978, do you think?
3. What is the best way to clean the tile and grout if the CLR is acidic and dissolves the grout over time? Sometime, I seem to see yellowish mold on the grout.
4. Is there any stronger grout material to use these days that can withstand the acidic diluted CLR rather than the regular unsanded grout?

Thank you.

 

[DIYorBust]

It's best for water to not get behind the grout. In newer installs there is a waterproof membrane behind the tile, but in a 40 year old installation I'd say that's very unlikely. Without seeing the holes, I can't say if I'd be concerned about them. If the hole is in a place where water enters it frequently, I might try to fix it. If it was truly tiny I might not bother. You can get a grout matching panel, find something that matches, and pack a little grout into the hole, or use a hand held grout saw to remove some grout and remake a larger area.

Epoxy grout would be more resistant to CLR, but I'm not sure I'd recommend that here. If you think the CLR is too harsh for your grout,t ry one of the many products designed for grout cleaning.

 

[Jadnashua]

Thank you jadnashua very much for the comments.

In the past after I cleaned the bathtub wall regularly with diluted CLR, I noticed that the grouts were worn down, looking porous a little. So, I clean less with CLR these days.

Can I ask some more questions on this?
1. Right underneath the tile and grout, there is some kind of cement mortar so that any kind of wood like stud is not in direct contact with any water coming from the tiny hole in the grout. Is this correct?
Depending on the age, ideally, there would be what is called cement board (cbu) beneath the tile. The tile could have been installed on plaster (not great, but can last a long time), or plain drywall (a disaster waiting to happen). Today, they'd also install the cbu over a sheet of either plastic or roofing felt on the studs to help protect them. Hard to say what's in yours.
2. I learned a new word, weep hole. Thank you. I looked up for the bathtub, and I did not see any slit near the surround of the bathtub looking like the weep hole. Was it the standard for a house built in 1978, do you think?
Weep holes are only used in shower drains where you have a clamping drain with a liner, not on a tub. Now, some surrounds (generally not tiled, although it's not a bad idea), Some surrounds may have them, but there's none in a tub's drain.
3. What is the best way to clean the tile and grout if the CLR is acidic and dissolves the grout over time? Sometime, I seem to see yellowish mold on the grout.
Acidic cleaners shouldn't be your regular cleaning material for things with cement. Cement contains some calcium, and calcium will be dissolved by acids. That will also tend to make the grout coarser as it leaves the sand particles (assuming it's a sanded grout, yours may not be if the joints are small) less supported. There are some things that will help clean and inhibit mold growth on grout. One thing you can make from stuff you may have in the house, a mix of borax, hydrogen peroxide, and alcohol. There are commercial mixes designed to help clean and inhibit mold, one I use sometimes is called Moldex. If the grout is just stained, there are grout cleaners available. A home remedy for that is to mix some baking soda and vinegar and scrub with a tooth brush. The vinegar is a weak acid, so on any that are, you want to rinse well when finished.
4. Is there any stronger grout material to use these days that can withstand the acidic diluted CLR rather than the regular unsanded grout?
There are lots of different grouts today other than cement based ones (but they all tend to cost more): acrylic, epoxy, urethane based ones come to mind. Still, there's a huge amount of cement based ones used...they tend to be stronger, and harder. If you use a cement based grout, it doesn't hurt to apply a sealer. It won't stop grout from staining, but it slows how fast things are absorbed, and gives you more chance to clean it up first. Sealer is sort of a misnomer, but it does help some. If used, the grout must first be clean and dry and you need to follow the instructions on how long it should sit prior to allowing it to get wet again.

Thank you.

 

[Dj2]

At 40 years old, your tub surround is not new anymore, so holes in the grout, missing grout and cracks are to be expected.
Chances are (or at least you hope) that what's behind the grout was done to code and your moisture barrier is still there.
At some point, your bathroom will be remodeled, and the tile work will be re-done. Am I wrong?

 

[JasonM]

Thank you DIYorBust, jadnashua , dj2 very much for the comments.

DIYorBust, I covered it with the packaging transparent tape temporarily. So, it is safe for now. I am going to repair that area with unsanded grout later. Since I learned that CLR is strong and effective, but too harsh, I am going to use baking soda and vingear as jadnashua suggested below.

jadnashua, thank you for the detailed answer. I learned another new word, cbu. I looked up Moldex, and it is rather expensive for a cleaner. There are many kinds of grouts, I noticed, and I have to study a bit to see what is best for me. Probably, I will use again the unsanded grout with sealant and not use the CLR in cleaning. Since you explained it, now I see why the wear-down was accelerated after I started cleaning it with CLR.

dj2, as you said, I hope there is some moisture barrier behind the grout and tile. You are right in saying some day, the bath will be remodeled.

Can I ask one more question related to bathroom?

In the same bathroom, I have the 2-door bathtub door and frame in gold color aluminum. I think it is aluminum, and there is regular white color silicone where the bathtub door frame and bathtub wall tiles join. On that silicone, there is some blackish mold. I found out that if I use paint lightly with a brush the Clorox gel on the silicone mold, it disappears. I think it is killed.

If I accidentally brush the Clorox gel on to the aluminum frame, will it be discolored, damaged, or rusted?

Thank you.

 

[Jadnashua]

The gold color is the result of anodizing the aluminum. That creates a very hard, but thin coating on top of the aluminum. I'd try putting some of that mix in an out of the way area to test.

FWIW, you almost never actually see raw aluminum. Aluminum wants to become more stable so badly, that it can actually strip the oxygen out of iron rust (it's called a thermite reaction - once you initially get powdered aluminum and iron rust together hot enough, the aluminum will literally exothermically heat up the iron so hot that it becomes molten as it strips the oxygen out of the rust, leaving liquid iron). The big difference between iron rust and aluminum rust is that iron rust is bigger than the elemental metal, pulling the rust off the base metal, exposing that to more oxygen. Aluminum rust, OTOH, is the same size as elemental aluminum, and creates it's own one molecule thick (so it's transparent) aluminum oxide coating, so it stops rusting unless that coat gets damaged.

If you've picked up a small shell you don't care about keeping, pour some vinegar into a glass and drop the small shell into it. Over the next couple of days, look at it periodically as it dissolves from the acid. So, vinegar is still an acid, so you need to be careful, but it's not as strong as what's in CLR I don't think. The calcium in the shell is the same material as is in cement grout, concrete, and thinset.

If you buy undiluted MOldex, a gallon will make something like 40-50 spray bottles at a concentration you'd normally use.

 

[DIYorBust]

If mold is growing on your caulk, you should recaulk that joint as the mold retardants have likely lost their efficacy. As a DIY I prefer to use a mold resistant latex caulk, and I've been very happy with polyseamseal. The advantages are that it is much easier to remove and recaulk since latex caulk will stick to old latex residue. Also a more attractive, less visible caulk line can be made since it is easier to tool, and obviously soap and water cleanup is much more forgiving than mineral spirits cleanup. I think plumbers prefer silicone because it has a shorter time to cure for wet use, and it is reliable and lasts a long time. This will result in fewer callbacks, and happier customers since they can use the shower after a few hours. But I find it easier just to recaulk every 5 to 10 years and keep it looking nice, versus spending hours with a razor blade scraping out the old caulk.

 

[JasonM]

Thank you jadnashua, DIYorBust very much for the comments.

jadnashua, I thank you for the detailed explanation, but I do not know the ABC's of chemistry. Next time I get the sea shell, I will try putting it in a vinegar.
Since the Clorax bleach gel may damage the gold color frame, I will tape the frame so that it is covered when I apply the gel.
I will use the cheap easy method of using vinegar and baking soda to clean the grout instead of introducing another product in my cleaning tool set. I saw somewhere on the web that CLR is 15 times more effective than vinegar, which I think would mean 15 times stronger.

DIYorBust, I thank you for introducing a new product, polyseamseal. I did not know the product. I will take a look and try using it next time.
BTW, I am not sure if you know this or not, but if you have silicone caulk in the bathtub area and has a black mold, there is a very cheap and easy way to clean it with Clorax Bleach Gel. I used it several times and it is very good, clean like new. Here is the probably original video on how to do it.

Thank you.

 

[Jadnashua]

Polyseamseal was sold to I think DAP, and is now sold as kitchen and bath caulk.

Ever been to Carlsbad Caverns or some other underground cavern? THey're all in limestone country and the rainwater falling through the air picks up a little CO2 and creates a weak acid. Over 10's of thousand of years, it eats away the rock to make the cavern with it's stalactites and stalagmites. A shell is made of about the same material, and it will be dissolved by any acid...the strength will determine how fast.

 

[DIYorBust]

https://www.acehardware.com/departments/paint-and-supplies/caulk-and-sealants/caulk/1220466

This is the product I used.

 

[JasonM]

Thank you jadnashua, DIYorBust very much for the comments.

jadnashua, you have deep chemistry knowledge. You must be a chemical engineer.

DIYorBust, thank you for the link. Next time, I will try using that product.

Thank you.