Hi Jill. Marble is very porous. So is regular grout. It will absorb moisture. It is good that a shluter pan was used. Hopefully the entire system was used over the cement board on the walls. If not or another water proofing agent was not used, you will have trouble down the road. Epoxy grout, although difficult to work with, is also virtually waterproof. This is normally not used but with the porosity of the adjacent marble it wouldn't hurt. It does appear that moisture is entering the stone from the edge where the grout is at. At this point I would recommend making sure that the very best sealer you can find has been used. I would consult a professional supplier of tile and stone installation supplies and see what they recommend. One here in Cleveland that we use is All Floors Supply. Once you determine the best sealer, make sure it has been applied very well. Grout and marble suck up sealer and can take multiple applications. Hope that helps.

That is one of the disadvantages installing marble in the shower because marble is a soft stone and it absorbs everything and will require lots of maintenance, especially when dirt will start to penetrate the surface it will be harder to clean because it is very easy to scuff the surface.

Most tile installers will recommend staying away from marble in the shower or other wet areas.

Ugh. Thanks for your reply. I have sealed it. Is there anything else I should do? Does the grout look normal?

Another thing I thought of is to make sure WHITE thinset was used, not grey! Grey thinset will discolor marble just as you are seeing, especially in wet conditions. I personally have marble in our shower and have had it installed in many others without an issue. The cleaning issue is more because it etches with acidic cleaners so neutral cleaners must be used.

White thinset was used. Still, I am disappointed in how it looks when wet.

I would start with the sealer then. Call Greg at All Floors Supply in Cleveland. He will ship to you any products they recommend. Explain to them the situation and they will make a recommendation. It may be something you have to deal with but at least you have covered all the bases.

Sealer doesn’t make a sponge waterproof. It just makes it more stain resistant. Sealer doesn’t prevent chips, etches, impact stars, or anything else that happens to marble. You chose little hard sponges to cover the walls of your shower. It’s going to absorb water. Period. Your marble is behaving like marble. If that disappoints you, then you didn’t do enough research.

How long after grouting did you wait before using the shower.

We waited four days. The sealer I used said to seal 48 hours after grout and then we waited anther 48 for it to cure, mostly because we were busy.

Jill, don't drive yourself crazy, it's the type of the stone not much you can really do...

Marble is beautiful like no other stone but it can be a real pain in the A$$ because of high maintenance requirements and it has to be cleaned and sealed regularly, it becomes a full-time job... I hear this all the time from my friends who installed marble tiles in the shower and some regret and some live with it. In addition, marble can be only cleaned with mild soap solution or specific products designed for marble. Same goes when you put a drink on the Marble surface or if you spill something you have to wipe it right away because if you don't, you end up with a stain.

We always talk customers not to use marble in the shower because most of the time it becomes a headache not only for a homeowner but for the contractors as well because many think you put the tile in, you seal it and you forget about it... I wish it was that easy. People start calling when they get a stain, etc and they think it wasn't the right sealer, or it wasn't sealed right, etc and no matter what the contractors do, the stone reacts in its own natural way to the environment it's in and not much anyone can do.

So enjoy your shower and maintain it per manufacturer guidelines and try not worry about it.

Good luck.

This is why you don't use marble in an everyday shower. If it is polished it usually can't accept sealer as the pores are closed up. The idea what sealer is to keep applying till the stone no longer accept any more.

People can discuss this all day but in the end it is the stone. People buy products based on looks vs functionality. I find it hard to believe the tile store and installer both didnt warn you of this before hand as most have you sign a waiver because marble always causes an issue with homeowners as they never understand that natural stone acts like natural stone.

Notice how it is wetter by the grout. A hybrid or epoxy grout would have been a better choice then there are some that argue the cementitious grout allows the stone to breathe.

In the end you have a beautiful shower. As long as they used the correct thinset, grout and waterproofing you should be fine. In this case I would say you need a roll on waterproof facing or some form of in front of the cement board waterproofing.

Learn to leave your shower door open to hale facilitate drying. Also watch the use of products with dyes as they will stain. Probably the most important is checking your water. If you have hard or any other water issue a house system could save you a lot of headache with those stones.

Its fine it dries out just get used to it.