I would like to use mosaic marble tile on my shower floor. Is this ok? If i do it do I need to seal it? My concern is not friction (this tile has plenty plus will have lots of grout lines) but the pourousness of the stone. Here is what Im considering from Lowes Home Improvement incase it matters.

mosaic marble tile

price of tile

4 Answers 4


The porosity of the tiles doesn't matter - the waterproofing happens on the layer below. You'll want to use something like Kerdi (the Kerdi shower pan kit is nice) or a similar product, or RedGuard, or another form of waterproofing.

The problem with marble is that it's a limestone type of stone, and susceptible to chemical attack. Over time it will lose it's gloss and go dull. How long this takes will depend greatly on your water and the products you use. It might only last a few years or it might outlast you. When it dulls you can either polish or replace.

JohnBridge.com is a tile forum, and the topic of marble showers has been discussed there. You might get some good info by browsing old topics. And John Bridge himself has a marble floor in his shower and wrote an article about it. He lists a recommended sealer and has some brief instructions on using it, too.

  • Thanks for your answer. Someone i spoke to said to seal the marble on the floor because otherwise the grout will crack from water penetration on the sides
    – n00b
    Dec 28, 2016 at 22:46
  • although based on your answer im guessing you would say the grout doesnt need to be sealed either?
    – n00b
    Dec 29, 2016 at 2:26
  • I think that ceramic tile impermeable to water and with the right coefficient of friction when wet would be essential for a shower. Is marble durable enough and does it give secure footing for a shower? Dec 29, 2016 at 4:01
  • 2
    When I said the porousness doesn't matter I mean in terms of keeping the underlying structure dry. So if you choose porous marble or impermeable glazed ceramic it makes no difference - the tile isn't what makes a waterproof shower, what's below the tile is. The sealing is to protect the grout and tile from staining. You can't count on it to keep water out of your structure, it's not intended for that purpose and it's neither durable or long-lasting enough to count on anyway. Sealing will slow down the staining & etching process I mentioned in my answer
    – Sean
    Dec 29, 2016 at 14:37
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    @n00b I think what he's getting at regarding durability is the PEI rating. It ranks tiles into groups based on how much foot traffic it can take. Gr I rated tile is only god for wall use due to durability. This tiles does not have a PEI rating so IDK. To me marble is marble, and there are marble floor tiles out there. But if they say not to use it on a floor; maybe they have a reason? I'd use it but I'm a risk taker. And not 100% on topic but if you can, check out a local tile store. Usually a wide selection & good prices, and the sales staff usually knows their stuff.
    – Sean
    Jan 2, 2017 at 18:38

No you can't. My first thought on looking at this is that it isn't rated for flooring (marble breaks pretty easy if thinly cut).

And then looking at Lowe's specifications here it is not rated for any flooring use, including bathrooms.

  • Could you detail the reasons this would be bad (other then cuts being difficult)? I.e. what could go wrong
    – n00b
    Dec 29, 2016 at 5:32
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    The manufacturer tells you not to install it on floors. What could go bad? Well the marble might crack but probably what will happen is the top layer will rub off and the marble will become quite slick. After top layer rubs off (if there is one) it will stain and chip easily. The tiles you picked out are for walls.
    – DMoore
    Dec 29, 2016 at 5:36
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    Also note on the specifications that the marble is not rounded on its edges meaning any inconsistency in the height of the stone or thinset will result in possible bloody feet. Whenever you like a tile at a BB make sure it is rated to do what you want it to do. Pretty much anything can go on the wall but tiles must be rated for flooring. Yours even says its breaking point is 0-250 pounds of pressure! Surely it can take 1 pound.
    – DMoore
    Dec 29, 2016 at 5:40

I see no problem in using that tile for a shower floor other than the glossy pieces may need some light sanding to remove the fine finish: between soap and water, those pieces will become dangerously slick. These tiles will certainly NOT break under body weight as marble can typically sustain compressive loads of many tons per square inch, even the flexural strength of these small pieces is likely very high as well. The stated breaking point of 0-250 lbs. makes no sense whatsoever. It may refer to the entire 12"x12" "tile" which actually has no strength to speak of.

Water absorption is also not a problem. Unlike many limestones, marble is relatively non-porous and absorbs very little water. Being a carbonate, however, means that acids will react with your tiles and over time, may chemically wear them down. Depending on the mineral content of your water, these tiles may discolor into a dull, unattractive white.

I suspect that these tiles are (generically) "unsuitable for flooring" because marble scratches easily and wears down relatively quickly in most non-barefoot environments, especially when cut down into small sections like these.


From an installer’s point of view, the closer to Italy and Greece a stone is sourced, the better it will hold up in a wet environment. I’ve also noticed that more veining often indicates a higher iron content, causing the stone to change in appearance over time.

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