Sealing Marble Shower Tile & Grout

Carrara Marble Shower

Carrara Marble Shower


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 to know if I should seal the bathroom floor tile and what is the best sealer? Before sealing should I first polish/clean the marble?


The short answer.... SenGuard Permanent Stone Sealer is the best sealer for marble showers. It can be applied to both the tile and grout.

Why is it the best?

First, Senguard forms permanent bonds with the stone which means you only have to seal the marble one time. No periodic re-sealing is necessary as is required with all other sealers.

Also, its advanced technology allows for better penetration (particularly on dense, low-absorbency stones), more thorough coverage for enhanced protection against both oil and water-based stains and it's super-easy to apply.

But we're getting ahead of ourselves here assuming that applying a sealer is required. There's a bit more to the equation...

Do Marble Showers Need Sealing?

As a general rule you don't want to apply a sealer to marble or natural stone in a shower (with one exception discussed below) or other wet environments because you run into situations where the sealer may trap water in the tile causing many problems including degradation of the stone.

You may read or hear 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. Also, some marbles, granites and other stones are naturally dense, stain-resistant and don't need sealing.

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.

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.

Plus, 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.

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

Some people mistakenly believe that the reason to seal shower tile is to prevent the shower water from absorbing. No... also not the case (with one exception... see below).

Some water may absorb into the marble or travertine tile 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.

Exception to the Rule: White Marble Showers

White marble showers are an exception to the general rule to avoid applying a sealer in wet environments.

White marble like Carrara marble, Calacatta marble and others can contain small 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 sometimes occur from water behind the tiles and not simply from water absorbed while showering.

First, marble is not that absorbent and water would have to be on the surface for quite a long time (maybe 15-30 minutes or more) before it even starts to absorb.

Honed marble tile will absorb a bit more readily, but shiny polished marble tile has a very low rate of absorption and water may not absorb at all.

Also, since tiles are never really submerged in water in a shower, it is typically absorbed only into the surface (if at all), doesn't saturate the tile and dries quickly.

Thus, any iron deposits within the tiles (unless near the surface) are not exposed to water long enough to oxidize or rust and stains rarely occur.

Floors, benches and shelves are at greater risk for rust stains in white marble showers since water is left standing on these surfaces allowing more time to absorb and potentially oxidize embedded iron deposits.

Better safe than sorry; so, sealing white or Carrara marble shower tiles to help prevent iron oxidation is a good idea, although polished marble often can't be sealed as explained below.

Addition Marble Shower Sealing Tips

Poorly installed shower tile is a problem. You may have gaps, cracks or voids in the grout letting water flow 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.

If you decide you'd like to apply a sealer in the shower, then first perform the water test for sealing to determine if your marble could even absorb a sealer.

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.

Obviously, it would be absolutely useless to attempt to apply a sealer to a stone that can't absorb it and doesn't need a sealer.

Applying "just to be safe" doesn't work here. You're only looking for trouble. The result is wasted time, effort and money and a streaky sealer residue on the stone.

Waiting 2-3 weeks after shower installation is necessary 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. The "general rule" discussed above still applies, however, floors, benches, shelves or anywhere you may store products are at the highest risk in the shower but still pretty low-risk.

I suggest using one of these recommended marble & granite sealers.

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

No need to polish marble prior to sealing unless you are repairing etch marks. Better to repair first, but you can always re-apply a sealer to any spots where etch marks were repaired.

Sweep and clean the floor tile prior to sealing. Sealers don't form a topical coating, so it won't trap dust or dirt, but you want a surface free of gunk or debris to ensure easy absorption for the sealer.

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.

Still Confused
by: Todd

We've just installed white arabescato marble in a bathroom. It's on the floor, around the toilet, vanity counter, and shower floor walls and bench.

I've looked at multiple sites and am still confused on whether I need to seal the Marble and even then if it needs to be an impregnate seal. Can you shed some light on this? Thanks.

==== Countertop Specialty comment:

You should apply an impregnating sealer to the marble in the shower at least.

Now, the proper thing to do first is perform the "water test" (see link above for instructions) to determine if your stone needs sealing or not.

Polished marble often is very slow to absorb, and thus, at very low risk for staining. Such stones typically don't need sealing since they are already naturally stain resistant.

Also, if water takes a long, long time to absorb (15-20+ minutes), then it's going to be a problem to get the sealer to absorb as well. When a stone is already dense with low-porosity a sealer does not need to be applied.

If testing shows absorption in less than 10 minutes on you floor and vanity, then it may be a good idea to seal it to guard against stains. This won't guard against etching of course.

The shower is different only because of all the water. For nearly all other stone the water itself is not a problem and usually sealing a shower is unnecessary.

However, with white marble you have possible iron deposits in the marble that can rust if exposed to water causing rust stains on your marble shower tile.

For this reason, white marble tile showers should be sealed to prevent water absorbing and possible rust stain.

For dense surfaces like polished marble where getting the sealer to absorb can be difficult... you need to use a sealer that absorbs better like Senguard Sealer rather than a standard sealer.

sealing carrara marble showers
by: Anonymous

Thank you for this excellent advice. I find it very enlightening as I was about to seal my new marble shower.

Now I know to wait for 2-3 weeks to seal only the shelves and bench where products and water may lie for a time.

Greecian White Subway tile for shower
by: Marsha

I ordered 115 pieces of Greecian White Marble Subway tile, Premium Mosaics, for a walk in shower that is going to be built.

I was told at Home Depot, where I ordered it, that I would need to seal the tiles "before" grouting them and then "after" grouting. This is due to absorbency issues with marble tiles.

Is this true....because the tile guy at Lowe's said to not do that to their tile that I ordered for the back wall of the shower.

Of course their tile is mixed with white and tans. The reason I am asking is I don't want to do unnecessary sealing. I read your blog about white tile needing sealing but saw no mention of double sealing. Don't want to make a big mistake!!

==== Countertop Specialty comment:

Sealing marble tile or any stone tile prior to installation is sometimes recommended as a way to make clean-up after grouting easier, but this reason is very debatable.

The real reason you might want to seal marble shower tiles prior to grouting is if the grout is a darker color than the marble.

If so, the moisture and dye / color from the grout can absorb into the marble tiles creating a stain all around the edges which looks like a picture frame.

Such stains run through the full thickness of the tile, so it will be permanent.

However, if you are using a light-colored grout basically the same color as the tile, then you shouldn't have any problems of this sort and can wait to apply a sealer to the entire finished shower.

And yes, you do want to apply a sealer to white marble in the shower. Typically, shower tiles do not need sealing. No real risk of staining.

However, white marble contains iron deposits that can cause rust stains with repeated water exposure, so white marble shower tile is the one exception where you do want to apply a sealer.

I recommend using Senguard Sealer for Marble & Granite. It's the most advanced and permanent.

Enhanced sealer on carrara floor
by: KP

The contractor just laid a carrara floor in our master bath & used an enhanced sealer. We now see smudges & marks everywhere. Does anyone know what this is & why it happened?

==== Countertop Specialty comment:

Well, it depends on what these smudges and marks look like, but it could be due to sealer residue on the surface. It may be that the sealer did not absorb well and/or residue dried on the surface.

Try cleaning with acetone in a small area and see if it clears it up. Acetone won't harm the Carrara marble, but it will hopefully remove any residue.

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