New shower showing mold

Within the first year in our new house, our travertine noce mosaic shower floor began to get moldy, initially on the sides of the shower but now we see some interior squares getting moldy as well. Our shower is large but open. There is no door and it has a 3/4 open wall on one side. We squeegie the shower after every use and even the floor. We were told to seal it every six months and afraid we have not. We looked at the construction pictures and it shows they laid a mortar shower pan and it had black vinyl up the sides about 18" or more. I had someone with tile background look at the shower and he found some pieces of mastic at the top of the 3/4 wall which was not finished off so we don't know if they used this on the entire shower or just that area. He told us that mastic will mold and they should have used thinset. Of course he recommended we replace the caulking. How could this happen in such a new shower? I am past the warranty and sorry we didn't realize this is not normal until now. Is there a way to stay on top of it once we get rid of the mold.

 

Dear Merci:

 

“ We were told to seal it every six months and afraid we have not. ”

 

Thank goodness you didn't!

 

“ He told us that mastic will mold and they should have used thinset. ”

 

I really don't know if this is true. But if the mastic is not activated by water, it should not mold by itself. Which bring us to the only possible problem I can think of:

You must have water behind and under your travertine tiles.

Now, how did the water get there?

I don't know: only a physical inspection of your stall could determine that; but if I have to guess, I would have to assume that either you have no grout (maybe the tiles were set butt-joint) or some of the grout is missing or damaged.

And, BTW, you don't say anything about this, but your travertine is filled, right?

What to do if I'm right on the money?

Considering that travertine is one of the best stones for shower enclosures (providing that's filled, of course) due to its natural high-resistance to mold and mildew, when it begins to display mold and mildew throughout its texture, I'm sorry to report that usually the situation is too far gone for any possible repair.

I hope I'm dead wrong on this one, but it may be jackhammer time, alas… L

If the tiles were set butt-joint, than there's no doubt. What could one possibly do about it?

Let me know what your inspection will bring into the open and see if there's any hope.

And, in the meantime…

May I ask you to please read and e-sign our Statement of Purpose at: http://www.marblecleaning.org/purpose.htm?

Ciao and good luck,

Mauri z io Bertoli

 

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