KB Home \| Advanced Search \| Ask Question
Ask Your Natural Stone Questions

Limestone shower

Article Number: 591 | Rating: Unrated | Last Updated: Mon, Oct 8, 2007 at 12:00 AM

UGH!! I purchased a new condo with a large limestone shower. Within a few month I started to see what I believe is mold growing along the bottom of the wall and on the floor. First it was just black dots and a few splotches on the wall. The contractor tried to fix the problem by sealing it first with water base sealer and then with one that I believe is more of a wax base?? Within another six months we now have bigger reddish and black splotchy marks going from the floor up the wall. The floor is also cloudy. I was told by one rep that he thought water got sealed in under the sealer... I towel dry the shower after every use. I am not getting any answers from someone who I feel knows what they are talking about. After reading all your replies regarding limestone I am at a loss as to how to get rid of the "stains". I have tried bleach and water without any success. There are crack along the outside edge of the caulk lines. Is water being trapped behind the sealer and creating mold? If it is an installation defect, what did they do wrong? They just pulled up those tiles. What do i look for? At this time I still have the contractor returning phone calls but I don't know what to request to be done to solve the issue. Thanks for any help you have to offer!! It has been a year long nightmare!!

Dear Maurna:

first off, by saying limestone you're saying very little – if anything at all. There are many different (and I do mean different) kinds of limestone that span from dense and acceptable rocks, to limestone that will actually fall apart under running water, and everything in between. All in all, with a few exceptions, limestone in a shower stall is never a good idea.

That said for the record, let's forget about the stone right now, because in this case it has not much to do with it. Like in most cases, it is the human factor that created the problem - not the stone itself.

Let's take your case, for instance: even without seeing it, I can tell you that you have water under your stone tiles. It is so obvious that even a child could understand that! Probably you have grout or caulk missing along the floor and/or somewhere else. Or maybe the installer felt like being "italian" the day he installed your stall and set the tiles butt-joint... Whatever: you have water behind and under your tiles, and some "genius" decided that the best thing to do was sealing it in!!

No wonder that mildew and mold are growing from within!

And it is not certanly by trying to solve the problem from the surface of the stone that you're going to accomplish anything.

Without actually seeing your stall, I can't tell for sure, but there's the distinct possibility that the floor tiles may have to be removed and and new ones installed again - and properly this time, for a chance.

And no more sealing the next time; it's never a good idea to seal stone in a wet environment. You have to select the right stone and, above all, the right contractor. Nothing coming in a bottle could make up for the dificency of eitehr one of those two factors.

Of course you will also have to get the right intelligence on how to care for your investment, but if the stone is wrong and/or the installation is wrong, everything else is only a waste of breath.

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

Ciao and good luck,

Maurizio Bertoli

www.marblecleaning.org – The Only Consumers' Portal to the Stone Industry Establishment!