# Shower has MOLD..........



## opiethetileman (Apr 7, 2005)

Shower is roughly 14 months old. Went out today and did a service call to change out the valve in the shower valve. HO showed me dark spot in the pan. the pan is pebbles. i called my REP no return call yet.


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## angus242 (Oct 20, 2007)

What does Kerdi have to do with mold? I bet there's an issue with slope and the pebbles. 

I think when you see "Kerdi" and "mold-free" in the same sentence, it's a misnomer. Kerdi alone does not guarantee mold-free anything. I mean even a properly built water-in, water-out mud bed shower can remain mold-free for years too.


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## Leo G (May 12, 2005)

Same thing I was thinking Angus. The Kerdi does not have mold. The tile does. It might also be a person who doesn't do a good enough cleaning job too. The slope is the likely cause. Or the water just getting caught up on the pebbles and becoming stagnant. Either way a good cleaning with bleach will solve them.

Has to be done soon before the mold gets to deep into the grout and stains it permanently.


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## opiethetileman (Apr 7, 2005)

i only wrote the title to get attention. there is prper slope and its a 3x3 pan. drains pretty good as a fact. She has tried bleech and it came back. I am just asking for ways to go.


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## SLSTech (Sep 13, 2008)

Clean it, kill the mold, clean it again, let it dry for awhile & seal it - that is all you can do

As for the HO - run the vents for at least 15 minutes after the shower, no leaving wash clothes (shampoo bottles, etc...) on the floor, and remind them that they need to clean it regularry clean it & seal as needed

Oh & it's not cool tagging a product & saying it has X issue when it doesn't - just my .02


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## opiethetileman (Apr 7, 2005)

ok they are VERY VERY clean. They are both fitness people. Even if the water sit its supposed to drain thru the grout and hit the membrane and run to the drain?????? that is the basic principal to the shower system. Its a sunken pan. Kerdi over Denshield as well. Unmodified thinset I called schulter want them to send the rep out to look. Only thing I can think of by far is shower head over drip after its off. EXCEPT that is the purpose of the membrane. Its the only spots where it is. She has cleaned it with bleach and such. I told her lets get a answer and go from there. I think it was tec grout not sure on that one have to look up what she bought.


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## gideond (May 17, 2007)

Regular grout can easily mold. Even a little water setting on it too long can cause it. If this was a big concern, and it really should be when using pebbles, a grout containing Microban or a similar product should have been used to minimize these occurrences.


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## angus242 (Oct 20, 2007)

Cementitious grout is way more porous then urethane or epoxy. That's why I use what I use. I don't care about the membrane; if I can keep moisture from getting within the grout, I am better off.

My guess: basic cementitious grout, moisture is sitting within and not traveling towards the drain because of the pebbles. 

Solution: I'm not one that believes bleach kills mold. I have read enough that I believe it only "bleaches" the spores but doesn't kill them. Clean the mold with whatever method you believe will work. Dry out for a couple days, use a dehumidifier is if possible. Seal with quality grout sealer. Let cure recommended amount of time. Pray.


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## Tech Dawg (Dec 13, 2010)

If I'm not mistaken, microban will prohibit mold growth from underneath but your not guaranteed on top. Warm water, air and skin cells = mold, if they are not cleaning.


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## JohnFRWhipple (Oct 20, 2009)

I wonder what type of glue held the mesh sheets to the back side of the river rock.

If the glue wears down with water - what happens when they sit in a moist area for 14 months?

JW


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## Tech Dawg (Dec 13, 2010)

Good thought Jdub...
I always like the left field variables you throw out there... can glue break down and cause something like this?


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## angus242 (Oct 20, 2007)

I doubt the adhesive would be the culprit. If mesh adhesive was a problem, we'd see a lot more of this issue. 

For the mesh-backed tiles I've installed, most (if not all) of the adhesives have been water-soluble. Drop a sheet on the wet saw and the tiles want to release quickly.


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## JohnFRWhipple (Oct 20, 2009)

The mesh glue is a lot like Mastic I think.

I like the mesh backers that do not break down in water. 

Would not be to hard to set a half sheet with the mesh and another half with out and see what happens...

Not me of course - I'm three test subjects behind schedule already! :blink:


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## HandyHails (Feb 28, 2009)

FWIW I double the slope in pebble shower floors. Water can easily pool in the valleys and sit. Plenty long enough to start growing mold. Especially in a well used shower that does not have a long time to dry out.


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## tgeb (Feb 9, 2006)

Are you sure it's mold? What if a little iron got in the grout, or stones, or perhaps another mineral is reacting with the water....

Just throwing it out there..


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## ApgarNJ (Apr 16, 2006)

I can see people googling kerdi and coming to this thread now, being scared of mold, good job OPIE, haha.

I think people get so scared of a little mold when it might not be the hazardous mold anyways. Bathrooms are damp, the shower door is probably left closed after a shower, so how much air is really moving in there? usually bathrooms have small windows if any, so it's dark a lot in bathrooms.

it's the perfect growing area for mold. I don't see what the big surprise is. 

I believe angus has it right, the water isn't completely draining because of the pebbles. also, how do you know for sure they have a pre-slope under the kerdi? could be flat and not all the water is draining. 

mold loves dark damp places, that is just about every shower every built. all depends how much you scrub it and clean it. I know plenty of people who seem clean and the rest of their house might be clean but they have issues in the shower because I think everyone HATES cleaning tile/grout/showers/tubs. Tile has maintenance whether you have cement based grout of urethane, sad to say but most people are probably better off with swanstone one piece fiberglass walls because they aren't ready for the maintenance that comes with a fully tiled shower stall.


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## angus242 (Oct 20, 2007)

I agree with Josh....the slope with pebbles should be increased.

I just don't like the pebble floors. Too many issues for pure aesthetics.


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## opiethetileman (Apr 7, 2005)

I know there is a slope because I know the guy who put the shower in:whistling:whistling

I have to find out who the grout is??? and I agree I dont like pebbles ya do what you are told. Pretty doesnt get ya to the finish line. It just makes someone happy:whistling

I think I set 85% of that pan free hand no meshers


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## Tech Dawg (Dec 13, 2010)

SLSTech said:


> Clean it, kill the mold, clean it again, let it dry for awhile & seal it - that is all you can do
> 
> As for the HO - run the vents for at least 15 minutes after the shower, no leaving wash clothes (shampoo bottles, etc...) on the floor, and remind them that they need to clean it regularry clean it & seal as needed
> 
> Oh & it's not cool tagging a product & saying it has X issue when it doesn't - just my .02


Running the vent fan after the shower helps a lot but results are even better when it is run 15 minutes before taking a shower, as well... the room air will start circulating towards the vent :clap:


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## JohnFRWhipple (Oct 20, 2009)

*Second Schluter Failure*

Has your rep called back yet from Schluter? I bet you get the job repaired and fixed before he even touches base....

Great Customer Service :whistling

Next time you walk into a compression drain break out your Nobel Company Flashing tool and flashing ring. Then you can keep your waterproofing membrane on the top of the mortar bed and not underneath it.

And how come I never see you guys working with "Candle Wick" to help keep these weep holes from clogging. The "Wick" I have comes from my plumber wholesaler and is seven strands grouped together.










*Candle Wick - Luxe Drain*










*Candle Wick - Luxe Drain*


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