# mold in grout



## dayexco (Mar 4, 2006)

had our bathroom remodeled about 5 years ago.

tile guy did a beautiful job. noticed today though on the grout where the tile meets the tub, there is what i am assuming mold (grout is black) for about 3/4" long. no where else.

other than hire him to come back, grind it out and regrout that, are there any chemicals worth trying that would remove that black spot in the grout?


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## Inner10 (Mar 12, 2009)

Mild bleach solution and a tooth brush.


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## TNTRenovate (Aug 19, 2010)

No bleach, it's more dangerous than the mold, it only works on hard surfaces and is made up of mostly water, which mold loves. While it will clean up the discoloration it's not the best for actually killing it, especially in a porous surface like grout. There are plenty of non caustic, non hazardous solutions. You can find them at pretty much any hardware store.

Also, keep in mind the mold my be coming from behind the tile. Check for any cracks in the grout above the molding area.


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## dayexco (Mar 4, 2006)

TNTSERVICES said:


> No bleach, it's more dangerous than the mold, it only works on hard surfaces and is made up of mostly water, which mold loves. While it will clean up the discoloration it's not the best for actually killing it, especially in a porous surface like grout. There are plenty of non caustic, non hazardous solutions. You can find them at pretty much any hardware store.
> 
> Also, keep in mind the mold my be coming from behind the tile. Check for any cracks in the grout above the molding area.


maybe i should just bite the bullet and have him come back out, check it and do what he think best needs to be done


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## griz (Nov 26, 2009)

dayexco said:


> maybe i should just bite the bullet and have him come back out, check it and do what he think best needs to be done


Jeezuz, grind down a tooth on a 580 and dig the chit out....:whistling:laughing:


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## griz (Nov 26, 2009)

TNTSERVICES said:


> No bleach, it's more dangerous than the mold, it only works on hard surfaces and is made up of mostly water, which mold loves. While it will clean up the discoloration it's not the best for actually killing it, especially in a porous surface like grout. There are plenty of non caustic, non hazardous solutions. You can find them at pretty much any hardware store.
> 
> Also, keep in mind the mold my be coming from behind the tile. Check for any cracks in the grout above the molding area.


Finally, someone who understands something about mold...:thumbsup:


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## aptpupil (Jun 12, 2010)

It's one of those topics that seems to have a lot of bad information out there. What source do you guys trust for info on mold?


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## Inner10 (Mar 12, 2009)

It doesn't like basic environments, so anything with a high PH works in your favour, baking soda, oxyclean, chlorine etc.

I know Mike Holmes rants and raves about how dangerous it is, but we still put it in the water we drink, the pools kids swim in and the dishes we eat off.


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## TNTRenovate (Aug 19, 2010)

Inner10 said:


> It doesn't like basic environments, so anything with a high PH works in your favour, baking soda, oxyclean, chlorine etc.
> 
> I know Mike Holmes rants and raves about how dangerous it is, but we still put it in the water we drink, the pools kids swim in and the dishes we eat off.


Facts are facts. Even the EPA and OSHA have removed bleach clean up on all but hard non porous surfaces.

This has nothing to do with what any one individual thinks. It's just not effective on anything other than hard non porous surfaces for killing mold.

Yes it is used to disinfect water, but in controlled environments and with great care. It's not splashed about with little to no respect to is danger. 

It's is highly caustic and reactive. Not smart to use near ammonia products which are often used in bathrooms. It will discolor carpet, wood and other materials and is a skin irritant.

Why use it when there are much more effective products that are not nearly had harmful?


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## Inner10 (Mar 12, 2009)

TNTSERVICES said:


> Facts are facts. Even the EPA and OSHA have removed bleach clean up on all but hard non porous surfaces.
> 
> This has nothing to do with what any one individual thinks. It's just not effective on anything other than hard non porous surfaces for killing mold.
> 
> ...


I'm sure there are, bleach water and a toothbrush was what my mother use to use, worked then.


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## Inner10 (Mar 12, 2009)

We also cleaned the toilet with straight hydrochloric acid...that stuff was caustic.


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## TNTRenovate (Aug 19, 2010)

Inner10 said:


> I'm sure there are, bleach water and a toothbrush was what my mother use to use, worked then.


There are many things that past generations did when they didn't know any better. It's just not proven to do a great job on killing mold on porous surfaces. That's why I'm sure she had to clean up the same spot over and over with her bleach and toothbrush.


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## Inner10 (Mar 12, 2009)

TNTSERVICES said:


> There are many things that past generations did when they didn't know any better. It's just not proven to do a great job on killing mold on porous surfaces. That's why I'm sure she had to clean up the same spot over and over with her bleach and toothbrush.


True...so what do you use?


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## avenge (Sep 25, 2008)

TNTSERVICES said:


> No bleach, it's more dangerous than the mold, it only works on hard surfaces and is made up of mostly water, which mold loves. While it will clean up the discoloration it's not the best for actually killing it, especially in a porous surface like grout. There are plenty of non caustic, non hazardous solutions. You can find them at pretty much any hardware store.
> 
> Also, keep in mind the mold my be coming from behind the tile. Check for any cracks in the grout above the molding area.


I agree with this, especially the source of the mold. You'll pay someone to only remove the mold and if it's coming from behind the tile it will come back even worse.


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## TNTRenovate (Aug 19, 2010)

Inner10 said:


> True...so what do you use?


I start by scrubbing the surface with a detergent such as dawn liquid dishwashing soap. That will clean a lot of the surface mold and stain. Then use straight vinegar. It's effective on almost all molds and mildew. If that doesn't do the trick I do vinegar again and then top off with a backing soda scrub.


Off the shelf, I have used Krud Kutter Liquid Mold Remover. It's biodegradable and does a pretty good job.


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## dayexco (Mar 4, 2006)

Inner10 said:


> We also cleaned the toilet with straight hydrochloric acid...that stuff was caustic.


my brother who passed away was a plumber. i thought i remembered him using muriatic acid to delime toilets?

that stuff was naaaaaaaaaaaasty.


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## Inner10 (Mar 12, 2009)

dayexco said:


> my brother who passed away was a plumber. i thought i remembered him using muriatic acid to delime toilets?
> 
> that stuff was naaaaaaaaaaaasty.


That's what hydrochloric acid is.



TNTSERVICES said:


> I start by scrubbing the surface with a detergent such as dawn liquid dishwashing soap. That will clean a lot of the surface mold and stain. Then use straight vinegar. It's effective on almost all molds and mildew. If that doesn't do the trick I do vinegar again and then top off with a backing soda scrub.
> 
> 
> Off the shelf, I have used Krud Kutter Liquid Mold Remover. It's biodegradable and does a pretty good job.


Mold likes a slightly acidic environment, hence why I'd choose something alkali over vinegar.


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## TNTRenovate (Aug 19, 2010)

Inner10 said:


> That's what hydrochloric acid is.
> 
> 
> 
> Mold likes a slightly acidic environment, hence why I'd choose something alkali over vinegar.


While it is "acidic" It's an acetic acid, which is pretty good at killing mold. Combined with baking soda it pretty much will kill any mold and bacteria.


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## Inner10 (Mar 12, 2009)

TNTSERVICES said:


> While it is "acidic" It's an acetic acid, which is pretty good at killing mold. Combined with baking soda it pretty much will kill any mold and bacteria.


If you mix those two together they are pretty weak, you get a little carbonic acid and sodium acetate...but it's mostly water.


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## dsconstructs (Jul 20, 2010)

http://www.concrobium.com/faq/

Very effective stuff.


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## Inner10 (Mar 12, 2009)

TNTSERVICES said:


> Do you often get your panties in a bunch when someone doesn't agree with you on everything you say? I did read and comprehend. You said it's safe, when there are dangers involved. Ignoring them doesn't make them go away. If someone has used an ammonia cleaner in the shower that would be a bad combo. That's just one example.
> 
> You also suggested to try it first and if it doesn't work go another route. Well, it won't work. It might clean the surface but it won't kill the mold in the grout. So why try something that isn't going to last as a long term solution. Sounds like a waste of time and money to me.
> 
> ...


Based on your analogy I could just dump bleach in the tank of my car instead of gasoline.:whistling


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## TNTRenovate (Aug 19, 2010)

Inner10 said:


> Based on your analogy I could just dump bleach in the tank of my car instead of gasoline.:whistling


If you say so. But the way I see it, I said bleach and gasoline were on the same level of toxicity to humans, not that they were interchangeable in use. But when it was compared to vinegar as being "caustic", I simply illustrated that while it could be labeled "caustic", it's not caustic or toxic like bleach, as it is used as an ingredient in commonly consumed food products.

Bottom line to my point is Bleach is toxic, highly reactive and not a very good cleaner or mold killer in porous surfaces.


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## 91782 (Sep 6, 2012)

Inner10 said:


> Based on your analogy I could just dump bleach in the tank of my car instead of gasoline.:whistling


Not your car, just Rob's.


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## superseal (Feb 4, 2009)

Mold Armor is a very popular choice and claims to work on hard, as well as porous materials. It's main ingredient is Sodium Hypochlorite. When I read Clorox's safety data sheet, there's the same mention of chemical. 

I'm not a full believer that standard household bleach doesn't absorb and kill mold/mildew beyond the surface of porous materials.

http://www.homedepot.com/catalog/pdfImages/89/89b9c3e0-e9dc-4fa4-bdde-708a2cacaf28.pdf

https://www.thecloroxcompany.com/downloads/msds/bleach/cloroxgermicidalbleach1jw2014-08-24.pdf


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## superseal (Feb 4, 2009)

Here's what mold armor claims it works on... http://www.homearmor.com/product/mold-stain-blocker


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## TNTRenovate (Aug 19, 2010)

superseal said:


> Here's what mold armor claims it works on... http://www.homearmor.com/product/mold-stain-blocker


This is at the bottom...priceless:

_" If necessary, reapply every three months or when odor, staining, and discoloration due to bacteria, mold stains, or mildew stains return."_


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## GO Remodeling (Apr 5, 2005)

I.........agree.........with............Rob! (Did I just say that?,lol) Bleach is a so-so cleaner of mold. Of course, you would dilute it to make it safer to use. But there are more effective, longer lasting and safer cleaners available. 

What was the topic again? :laughing:


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## 91782 (Sep 6, 2012)

I am of the opinion, that at some point in time, no matter what the substrate, or the sealer, or the superior workmanship in the install process, its a matter of "when" mold occurs, not the "if".

And whether you just eliminate the cosmetic effects, or "kill it", its going to come back again. If not the same spot, then a new one.

No grout lasts forever, no caulk lasts forever, no two materials once joined together will forever maintain an impermeable surface.

What amazes me, is when I/we have done tear outs in really old - I mean 1900 era houses with tile work not much different than the Romans used - how little hidden mold there is.

Old tarpaper and asphalt and lead sheeting.


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## EthanB (Sep 28, 2011)

Concrobium, Microban and Fiberlock all make professional products for mold removal. I don't think any of it comes in small quantities or cheap, but I haven't looked for them.


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## TNTRenovate (Aug 19, 2010)

If you remove as much of the food and environment they thrive in, invasive mold and mildew shouldn't really ever be an issue, especially with regular cleaning and good ventilation.

We try to install showers and tubs with mold and mildew in mind.

1) Ventilation in the wet area itself controlled by a timer. Educating our customers on running it 20 minutes after the shower or bath is complete.

2) Kerdi board and Durock as our main substrates (both do not provide a hospitable environment).

3) Try to stay away from porous stone (travertine)

4) Urethane or Epoxy, both of which are not porous.

5) Moved away from grout caulks and towards mildewcide caulks.

So far so good.


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## dsconstructs (Jul 20, 2010)

I know for sure Concrobium comes in 32 oz spray bottle for less than $10, gallons about $30. Not sure about the others.


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## 91782 (Sep 6, 2012)

Concrobium: Interesting that the listed active ingredient is Sodium Carbonate (washing soda).

The listed ingredient on the MSDS is TSP (Tri-Sodium Phosphate).

www.concrobium.com/faq/

"Sodium Carbonate is the listed “active ingredient” on the Concrobium Mold Control label, but in fact there are two other ingredients in the solution which, when combined with the sodium carbonate and the water, result in this patented tri-salt *polymer* that eliminates and prevents mold."

And then they go on to describe the resulting mixture a "polymer" - aka - a long chain molecule.

In any case, it is not a fungicide/mildewcide in the same category as those used to treat/kill wood rot molds - just basic off-the shelf chemicals that oxidize (burn) any organic compounds its put on.


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## Big Shoe (Jun 16, 2008)

First, scrape and clean all that fricking silicone off. Then use Zep grout cleaner and a grout scrub brush. Then re grout if needed. Seal if needed. Then re caulk with Polyseamseal Tub and Tile caulk. 


And just for the record, Depending on the circumstances I use straight chlorine on some tough mold issues. And diluted on others.


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## dsconstructs (Jul 20, 2010)

SmallTownGuy said:


> Concrobium: Interesting that the listed active ingredient is Sodium Carbonate (washing soda).
> 
> The listed ingredient on the MSDS is TSP (Tri-Sodium Phosphate).
> 
> ...


True....and it works though. We're not talking about killing wood rot fungi. I'll admit that sometimes I'll use bleach based products for quicker cleaning. Products like concrobium just don't clean the staining as fast without extra scrubbing. I do rinse well, let dry and then treat with concrobium after. You just have to spray it on and let it dry. 

I've seen the proof in my own house the last few years. Lots of fish tanks that evaporate so during the winter I had a few wall locations that would start getting mold, several times each winter I was cleaning those with bleach based products. Treated with concrobium and haven't had that problem again.


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## 91782 (Sep 6, 2012)

dsconstructs said:


> True....and it works though. We're not talking about killing wood rot fungi. I'll admit that sometimes I'll use bleach based products for quicker cleaning. Products like concrobium just don't clean the staining as fast without extra scrubbing. I do rinse well, let dry and then treat with concrobium after. You just have to spray it on and let it dry.
> 
> I've seen the proof in my own house the last few years. Lots of fish tanks that evaporate so during the winter I had a few wall locations that would start getting mold, several times each winter I was cleaning those with bleach based products. Treated with concrobium and haven't had that problem again.



I have no doubt that what you say is true.

The mention of wood rot products was simply to point out that these new "super products" do not rely on exotic, newly researched metals based compounds (like they use in wood products), but rather ordinary ones that have been around for hundreds of years.

Tri-*sodium* phosphate, *sodium* carbonate:

Well, once the oxygen reacts with the mold/mildew, what's left?

Sodium, aka SALT.

Salt is a pretty damned good deterrent to things that grow.

60 years ago, my mom would wash the bathroom down with bleachy soapy water, then rinse/buff with a bucket of washing soda water - to get the sparkle back.

A smart bunch that generation was.


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## dsconstructs (Jul 20, 2010)

Yea...my grandma used baking soda to brush her teeth.

On the side of wood rot fungi....like Timbor rather than copper green (napthanate)


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## 91782 (Sep 6, 2012)

TNTSERVICES said:


> If you remove as much of the food and environment they thrive in, invasive mold and mildew shouldn't really ever be an issue, especially with regular cleaning and good ventilation.
> 
> *We try to install showers and tubs with mold and mildew in mind.
> 
> ...


That reads good enough to put right into the warranty/service document. It is clear and states why you do what you do objectively.

One of the hardest things to do, is put in writing what the client must do to maintain the finished job and stay within warranty, yet not expose yourself (The Company) to claims, risk, or litigation.


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## rocspec (Nov 25, 2015)

I've seen this product used on remediation projects. Afterward, the wood framing was encapsulated with a paint on product. Check out the lit. It might be useful in a situation outlined by the OP.

http://www.fiberlock.com/mold/8310.html


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## MarcoPollo (Dec 6, 2014)

TNTSERVICES said:


> If you remove as much of the food and environment they thrive in, invasive mold and mildew shouldn't really ever be an issue, especially with regular cleaning and good ventilation.
> 
> We try to install showers and tubs with mold and mildew in mind.
> 
> ...


Could you link mildrewcide caulks? I'm intrigued. 

What is your process when grout colour us such that matching becomes difficult?


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