Sealing Marble Shower Tile & Grout


(from: Goran Ruvic, Coral Springs, FL) I just installed new marble tile in my bathroom on the shower walls and floor.

What is the best sealer for grout and tile in a marble shower.

Also, I need know should I seal bathroom floor tile and what is best sealer. Before sealing should I first polish/clean the marble?


As a general rule you don't want to apply a sealer to stone in a wet environment because you run into situations where the sealer may trap water causing many problems including degradation of the stone.

Yes, I know you may read that ALL stone MUST be sealed no matter what... just not true. It depends on the stone, the location and intended use of the stone installation.

Applying a sealer is done to reduce the risk of stains in marble or stone. This is very helpful in areas like the kitchen, dining room or high use floors or countertops in a bathroom.

However... the risk of staining in marble showers is near zero unless you regularly toss a salad or drink some wine in there!

Think about it... you use very few products in the shower, and when in use water is constantly washing them down the drain.

You'd have to leave a leaky bottle of something sitting on the marble tile for it to ever have a chance of staining.

And even if it did, marble stains can be removed in nearly every case.

Some people mistakenly believe that the reason to seal shower tile is to prevent water absorption. No... also not the case.

Water may absorb into the marble or travertine tile some while showering, but it quickly evaporates and does not cause any problems.

You don't gain any real benefit by applying a sealer, since your stain risk in a marble shower is minimal. BUT... you do risk creating unwanted problems by sealing a stone in a wet environment.

In truth, the sealer itself won't "cause" a problem out of nothing, so don't worry if you've already sealed your marble shower.

However, in a case where water gets behind the tiles of a sealed shower, it will block evaporation potentially making damage a lot worse.

One possible exception here are honed white marbles like Carrara marble. White marbles can contain iron deposits. Water can oxidize these deposits, which may lead to a rust stain that is difficult to remove.

This is most often a problem on floors after a flood or from a plumbing leak. Meaning the tiles and the iron deposits must be exposed to water over an extended period of time or from a continuous source.

In a shower, this could occur from water behind the tiles, but usually not simply from water absorbed while showering. Shower water is typically absorbed only into the surface, doesn't saturate the tile and dries quickly.

Thus, any iron deposits within the tiles are not exposed to water long enough to oxidize or rust and stains never occur.

However, sealing honed white or Carrara marble shower tiles to help prevent iron oxidation isn't a bad idea. (Polished marble usually can't be sealed as explained below)

Now, poorly installed shower tile is a problem. You may have gaps, cracks or voids in the grout letting water behind the tiles where it gets trapped. But sealing won't help a lick in this instance... in fact, it would make it worse as noted above.

Plus, even if you wanted to apply a sealer, you may not be able to. Marble actually is not very porous and does not stain easy.

Marble will etch easy and people always confuse etching (whitish dull spots from chemical corrosion) with staining, but these are two different marble maintenance issues.

In particular, polished marble (vs. honed) has such a low rate-of-absorption that it's nearly stain-proof.

Sealers must absorb into the stone to work. Dense, low-absorbency stones (like polished marble) typically do not need sealing and often "cannot" be sealed because the sealer won't absorb.

If you're bound and determined to apply a sealer in the shower, then at least you should first perform the water test for sealing to determine if your marble could even absorb a sealer.

And then, be sure to wait 2-3 weeks after shower installation before applying a sealer to allow the stone, grout and all installation materials to dry out completely or you'll trap water in the stone.

Sealing the bathroom floor is not a bad idea though. I suggest using one of these recommended marble & granite sealers.

SenGuard is the best available.... head and shoulders above every other on the market. We really like this product and highly recommend it.

You must wait two to three weeks to seal floor tiles, as well, to allow time for all moisture to evaporate.

Sweep and clean the floor tile prior to sealing. Sealers don't form a topical coating, so it won't trap dust or dirt. It's just easier to apply to a clean surface.

Marble polishing is done on specialized, high-friction machines at the factory. It's not something that you would or could improve, so no worries there. Just cleaning the marble is fine.

Comments for Sealing Marble Shower Tile & Grout

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by: Alvaro Castellanos

very good article good description

Thank goodness for this artical
by: Anonymous

I didnt buy marble for my tub area for it to be another headach of having to baby another project around the house. After doing the lemon and oil test it seems i have a very hard polished marble that is not porus and does not have to be sealed like most other sights tell a person that they should. Thank you for this artical

happy,happy,happy I read this!
by: julie

We just invested so much in the marble and Granite. So you know we want to keep it new forever!

This article kept us from putting anything in our shower (floors, seating, walls). We only had to do the large floor of marble. cha ching!

And the granite counter tops are a dark gold, brown & black, so, nothing to do there! cha-ching! thank you

===== Countertop Specialty comment:

Just FYI... your granite countertops may need sealing. Darker colors often do not need a granite sealer, however, the only accurate way to know if your specific countertop slab should be sealed or not is to perform the
water test for sealing granite.

Carrerra White Marble Shower
by: Anonymous

So I read your comments .... we have installed Carrera White Polished Shower Tiles (we had them installed) in our walk in shower, around the shower sill, around the marble vanity, and then larger tiles on the floor.

Do you recommend sealing ALL or just outside the shower area?? Thanks in advance.

==== Countertop Specialty comment:

White marbles like Carrara can develop rust like stains due to oxidation of iron deposits within the marble. Oxidation can occur with repeated cycles of water absorption and evaporation.

Now, water absorbing is not a problem for the marble. With most marble there is no need to seal simply to keep water from absorbing (i.e. in a shower).

However, you do want to seal white marble, Carrara marble in order to prevent rust / oxidation stains from water contact.

I suggest applying a sealer to all surfaces that will be regularly exposed to water. Certainly in the marble shower, but possibly the floor, vanity top, etc. No real need to seal any walls outside the shower though.

marble mosaic on shower floor
by: Anonymous

We were planning to use a marble lattice moasic on the shower floor.

It is made of: Athens Gray, Asian Statuary, Wooden Beige
Finish: Polished
Sold by the Sheet- each sheet measures 13"x13" (1.17 sq.ft.)
Thickness: 10 mm

Would you recommend sealing this product if placed on shower floor since there is some white marble mixed into it?

And other care info I should be made aware of?

==== Countertop Specialty comment:

I would check with the manufacturer first, but yes.... white marble is the one exception where a shower should be sealed in order to keep water from oxidizing possible iron deposits that are common in white marble.

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