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.

Should I seal the marble tile and grout?

What is the best sealer for a marble shower?


Whether or not to seal a marble shower has arguments on both sides.

Some claim it's a must do while others say sealing showers doesn't really serve much purpose and may cause a problem in some cases.

Let's look at the reasons for and against and our take on it...

Do Marble Showers Need Sealing?

You may read or hear that ALL stone MUST be sealed no matter what... but that is just not true.

It depends on the stone, the location and intended use of the stone installation. For instance sealing marble kitchen countertops is usually a good idea.

Kitchens get way more traffic and abuse than bathrooms do.

On the other hand, some marbles, granites and other stones are naturally dense, stain-resistant and don't need sealing.

Problems can occur from sealing a shower. 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.

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).

A little water may absorb into the marble or travertine tile while showering, but it quickly evaporates and does not cause any problems. This is normal.

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 (from cracks or voids in grout or caulk), 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.

What is the Best Sealer for a Marble Shower?

If you do decide to sealer your shower or if y ou have a white marble shower, then SenGuard Permanent Stone Sealer is the best sealer for the job. It can be applied to both the tile and grout.

Or applying a standard quality impregnating sealer will work too but you just have to reapply it periodically.

Why is Senguard 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.

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.

You can spot this problem as the shower tiles will start to turn gray or darker. Usually, the floor tiles are most affected but you may notice the wall tiles that touch the floor become darker as well.

What happens is the water behind the tile absorbs into the tile and darkens it. White tile like Carrara marble will look gray.

Often you'll see that half of the wall tile is gray or darker. This occurs as the water from the floor rises up inside the wall tile. Again, this is from water trapped behind the tiles.

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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Best Grout Between Shower Floor & Wall?
by: Larmijo

My 4yo shower walls are 6x12 Carrera marble tiles.

The original grout between the wall and floor cracked, allowing water to seep under which stayed a long time until I noticed it.

Some tiles were darker, and a few have rust stains which appear to be where the adhesive is (where the tile was cemented to the cement board in the wall).

All tiles are sealed. I removed that grout (non-sanded) and replaced it with silicone sanded grout.

After a year this also allowed water to seep behind. I have removed it, now waiting for all tiles to dry.

My question: should I have the lower course of tiles removed to replace the backer board in the worst area?

Can it hold water?

Once dry, which grout to use?

My house is 60yo, on pier & beam, which does adjust to seasonal changes. Thank you!

==== Countertop Specialty comment:

The repeated problem you are having with the grout between the shower wall and floor cracking or separating is almost certainly due to the foundation shifting.

Sanded grout is the best grout to use in the joint between the shower wall and floor. It should last for years unless other forces (like foundation movement) are affecting it.

But in your case, I'd suggest using 100% silicone caulk. The caulk will expand and contract better with the foundation movement than the grout and should last longer.

Don't caulk the joint until the shower dries out completely, you remove rust stains, fix the backer board, or whatever other repairs or tile replacement you may do.

The lower tiles got darker because they got saturated with water. They should return to their normal color after the water evaporates.

The rust stains are probably from the oxidation of tiny iron deposits embedded in the marble itself.

They could be from a reaction with the adhesive, but probably from iron deposits oxidizing.

White marble often has these embedded iron deposits and when exposed to water will cause rust stains.

We see this regularly in Carrara marble or other white marble showers.

Sealing white marble tile in a shower is a must.

But if water does get behind the tiles or saturates the tiles then not much you can do to prevent the rust stains.

You can try to remove the rust stains using the Marble Rust Stain Remover, but I wouldn't expect miracles.

Rust stains from embedded iron deposits are next to impossible to remove since the stain is originating from within the marble tile and is too deep.

But can be worth a shot. Otherwise, you'd need to replace the tile.

Regarding the backer board, etc... that is a question for an on-site professional to assess and answer.

Is Tuscany Cream Marble Considered White Marble?
by: Rose 2

Thank you for your informative site! I have read every word of all the comments, and still, I wonder if our Tuscany Cream polished marble (pretty light) is considered White and needs to be sealed.

According to the water test, it does not leave any mark after 15 minutes.

So, if it needs to be sealed, I believe the SenGuard is the only sealer with a hope to be absorbed.

This is a newly finished master bath that took much work to achieve.

It is just on the walls. The shower floor is cut beach pebbles and the floor tile is porcelain. The grout is epoxy.

It is beautiful and we want it to last a very long time.

==== Countertop Specialty comment:

No, Tuscany Cream marble is not considered a white marble and would not have the same level of risk for rust staining as a white marble shower tile like Carrara.

You could apply a stone sealer to the walls if it gives you some peace of mind, but I don't think it's really necessary in this case. At least not to prevent rust stains.

You should use the Soap Film - Hard Water Remover as your regular shower cleaner though.

It will safely and effectively remove all films that are the major cleaning issue in showers which lead to mold and dull tile.

Most bath and shower cleaners are too harsh for marble and will etch and dull the finish and should not be used.

Ghost picture frame around shower tiles
by: Carol

I read every line of this post and Q&A, and it is SO helpful.

Our situation is the same as many you cover, and a bit different.

We laid Firenze Calcutta mosaic tiles on our bathroom and curbless shower floor.

We'd only used the shower a handful of times when we noticed the tiles in a 12" or so ring around our drain had turned dark gray.

Our tile guys said to let them completely dry out and they would reseal.

It took about three months for the darkness to go away.

What's left around the edge of each tile is a white picture frame.

It doesn't seem to be efflorescence, as it's not on the grout. The grout is a light gray--darker than the tile, but since the "picture frame" is white, it doesn't seem like it could be the cause.

Our tile guys are willing to reseal to see if that will fix the problem. If it doesn't, they are only willing to take out the darkened tiles and replace them at our expense.

From what we've read from you, the problem is likely moisture from below from improper installation. Any advice you have for us would be greatly appreciated.

==== Countertop Specialty comment:

Yes, water under the tiles accumulating around the drain could be a cause, however, if it took 3 months without using the shower for the darkness in those tiles to go away, then some other factor must be involved.

I don't think it would take 3 months for the water to evaporate from the tiles if indeed it was water absorption darkening the tiles.

And now you have a white picture framing around the tiles that surround the drain. That is a twist for sure.

Normally picture framing would be darker like a stain.

But I gather it is happening only around the drain to the tiles that initially darkened right after minimal use.

Possibly it is a combination of water under the tiles and a reaction of the adhesive used to lay the tile on the shower floor and/or a product used to install the drain.

Honestly, this one is a complex problem and very hard to say for sure what the cause may be... or the solution needed.

Simply applying a sealer will not fix the picture framing. It may help with water absorption but usually, water gets trapped under the tiles from gaps in the grout or caulk and/or a problem with the shower pan.

Showers are wet environments so water may get behind the tiles but if properly constructed the water should run down to the shower pan and down the drain. It should not remain.

When there is a persistent problem that darkens tiles it is usually because an excessive amount of water is getting behind the tiles or a faulty install of the shower pan, etc.

I don't know why they are not offering to fix it at their cost. You did not cause the problem.

Personally, I'd insist they take out the damaged tiles, review the shower pan and drain install and reinstall new tiles all at their own cost. It's their work, they need to stand behind it.

Sorry I couldn't provide a more concrete answer. Definitely not a common or straight-forward problem.

Water Droplets Etching Heated Marble Floor
by: Anonymous

I have a beige marble tiled floor in my bathroom, and it seems that every day drops from wet hands (or wet kids) etch the floor.

I think this happens primarily or even only when the underfloor heating is on.

I have now used an impregnating sealer three times, days apart, and this seems to reduce the time before the water droplets begin to etch, but left to dry on their own they will still cause etching.

I live in an area with soft, not hard, water so this is especially perplexing.

Should I go ahead and seal it? Right now I polish out each drop of etching and this is a pain.

==== Countertop Specialty comment:

Yes, very odd. I'm assuming these spots remain at least a day after the water drops onto the floor, that they are not dark spots, and that regular wiping with a cleaner does not remove them.

A few points to discuss...

Marble etching explained:

Many people are confused about what marble etching actually is. Etching is a chemical reaction between a substance and the calcium carbonate in marble.

The chemical eats into the marble leaving a chemical burn that is dull and can look either clear or chalky white.

Sometimes you can only see an etch mark from a certain low angle or in certain lighting conditions.

This is different than a "stain" which is always a dark spot, is not dull, and can be seen from any angle.

So, if the spots you have fit the above description, then you have etching.

Heated floor and etching:

Heat can cause a chemical reaction to happen more quickly or not enough heat and it won't happen at all.

However, acid etching on marble occurs immediately upon contact no matter the temperature. So, I'd say it is possible that the heat is playing a role but not likely.

Water etching marble:

Pure water typically will not etch marble at all. It can absorb into the marble and create a dark spot stain, but that stain will disappear once the water evaporates.

I know you stated you have soft water, but just to clarify...

Hard water can leave behind minerals that form a dull or chalky spot or area but this almost never happens from just one drop on a random spot.

Usually, hard water deposits form over time in areas with constant water exposure like around sinks and in the shower.

Hard water deposits can look similar to etching in some cases, though. Etching can happen from a single drop where a hard water stain usually does not unless the water is really hard with a lot of minerals.

Soft water and marble etching:

Soft water has a lower pH level. The pH level is a measure of the acidity or alkalinity of a substance. Hard water usually has a pH of around 8-9.

Soft water has a pH around 6-7 which is "more" acidic than hard water but a pH of 6-7 is pretty neutral and should not etch marble.

When a household is using a water-softening system sometimes it can be set wrong and make the water even more acidic... maybe around pH 5.

A water pH at this level could potentially etch marble.

If your water is city water, then it shouldn't be too acidic but you may want to test it in order to diagnose this issue.

Sealing will not help prevent etching. Sealing prevents stains (substance absorbing). Etching is physical damage to the surface of the marble. A stone sealer cannot prevent physical damage.

How to test and diagnose etching:

I'd do a specific test on your marble to verify if indeed the water is etching your marble floor.

Spill a small drop of vinegar, lime, or lemon juice (anything acidic) on the floor and let it sit for 1-2 minutes. Do the same with your tap water right next to the vinegar, etc.

Do they form the same kind of spot (dull, clear or chalky)?

If so, then the water is acidic and etching.

But also note that whatever product you are using to "polish" out the current drops should also work on the etch spot you create with vinegar or lime juice.

There are many marble "polishes" but only a specific type of product like this Marble Etch Remover / Polish can actually repair etch marks.

And this is for a shiny polished finish. Repair of a matte honed finish requires a different product.

So, that addresses all the points in your question. Hopefully, it helps you diagnose the issue and apply the proper solution.

But if it is the water etching the marble, then I'm afraid there is no preventing it. You'll simply need to keep repairing and polishing the marble where the etch spots occur.

Applying a permanent topical coating would help to prevent etching, but coatings have their own set of problems and maintenance and are quite expensive. So, I would not recommend a coating.

Streaky Sealer Sealer Residue - Carrara Marble Tile
by: Lana

Your article was very helpful, thank you!

One answer I couldn't find though:

How do I remove streaky sealer residue left on my bathtub/shower walls after an unnecessary sealer application over polished marble?

It doesn't go away with regular cleaning.

Also, what is the best material to use to seal the gap between the tub and the tiles?

Regardless of the type of caulk I use (silicone or regular), it eventually cracks or separates from the surfaces because my family prefers baths and the weight of the water makes the tub level shift.

I did caulk with the tub full of water and even though it takes longer for the seal to break than if caulked with the empty tub, it still happens quite fast. Thank you for any insight and your time!

==== Countertop Specialty comment:

Good question about sealer residue... we should add that to the article.

To remove streaky sealer residue you'll need to use wash and scrub the surface with a solvent and non-abrasive scrub pads.

Acetone usually works best. Be sure to open windows and create good ventilation and wear some nitrile chemical-resistant gloves.

Acetone can be purchased on its own at any hardware store.

Acetone won't harm the marble or grout, but could be damaging to any cabinets or walls, etc., so mask off areas that need protecting.

In cases, where you notice streaking very soon after applying the sealer (like the same day) you can usually just apply a bit more sealer, scrub the surface a bit, and then wipe the surface completely dry.

The fresh wet sealer will usually take up the dried sealer residue and then you just wipe it all off.

You can try that now too, but usually once the sealer cures, you need to clean with a solvent.

About caulking the tub...

Silicone is preferred but the problem you are having has nothing to do with the caulk in my opinion.

If the tub is shifting that much, then I'd say it wasn't installed correctly. Certainly, there will be some flex but not so much that it pulls apart the tub-surround seam.

You had a good idea to caulk with the tub full of water, but I think the degree of movement of the tub is beyond the range of the caulk to flex and remain intact.

Marble Floor Heating, Grout Choice, and Sealing
by: Anonymous

Can you make a recommendation on the type of grout used for marble floors if they’re being placed on a heating coil.

We are using a dolomite 12x18 white tile on the floor.

Do you anticipate Any issues with the sealer on a heated floor?

Do we need more layers of the sealer?

==== Countertop Specialty comment:

You should be able to use a standard cementitious grout without any issues from the heating elements.

Of course, the different types of grouts now available has exploded so there definitely could be some that may react adversely to constant heat.

I'd check directly with the grout manufacturer on this.

Regarding the sealer... also, should not be a problem.

Do not apply the sealer when the heating coils are on and leave them off for at least 48 hours while the sealer cures.

Apply the sealer normally. Applying more sealer is not necessary simply because of the heating coils which should not affect the cured sealer in any way.

The sealer becomes inert chemically once cured, so mild heat won't have any affect on it.

Sealing to Prevent Mildew Stains
by: Anonymous

Shouldn’t a sealer be applied to all grout to prevent mildew stains?

Are sealers used for both sanded and non-sanded grout?

Thank you

==== Countertop Specialty comment:

Your question is a good one, however, there are several other variables at work. It isn't just a matter of sealing to prevent mold and mildew stains.

Sealing can help with preventing mildew stains, but the best prevention is to simply clean regularly, make sure the shower dries out daily, and the grout is not damaged allowing water behind the tiles.

Sealing would help prevent mildew from staining but not from growing. And if mold and mildew is left uncleaned long enough to stain the grout, then a sealer won't be of any use.

Sealers are not impenetrable shields. Stone sealers slow down absorption a lot and help but do not absolutely prevent absorption or staining.

Or if cracks in the grout allow water to get behind the tiles, then a sealer will be useless to prevent mold growth.

Same deal if the tile wasn't grouted well. A common mistake is not filling the entire joint with grout.

Too little pressure and/or not enough grout is used and so the gap is covered but the joint remains a weak spot for future failure and potential leaks.

The Mold & Mildew Cleaner will safely remove mildew without damaging a marble or natural stone shower.

But if you develop a consistent mold problem, then look to fix the above reasons for mold growth.

As for sealing grout...

Non-sanded grout is still porous but not terribly absorbent so sealing isn't strictly necessary.

But if you need to seal the shower tile, then go ahead and apply the sealer to the non-sanded grout too. It will just make it that much more stain-proof.

Sanded grout is porous and needs sealing. Now a well-made shower will absorb a little water and then it evaporates or runs down into the shower pan and no problems.

But since sanded grout is usually used on wider grout lines and is pretty porous it's best to seal it along with the marble or travertine or whatever stone tile you've installed.

Sealing Dolomite Shower Tile and Grout
by: Anonymous

I am putting dolomite tile on the shower and bathroom floors and around the toilet.

It’s mostly white with grey veining, polished, and very little water absorption prior to installation.

Using white grout. Planning to use porcelain mosaic for the shower floor.

1) Should the tile be sealed? In both the shower wall and bathroom floor?

2) Should we be using non-sanded or epoxy grout to limit water absorption?

3) Should we seal the grout while sealing the tile?

Thank you.

==== Countertop Specialty comment:

Dolomite and marble are close cousins. Dolomite is often component of marble and they do have similar properties.

I would seal white dolomite in the shower for sure. Probably a good idea to seal it on the bathroom floor and around the toilet as well.

The reason... white marble usually contains small embedded iron deposits that can oxidize and cause rust stains in wet environments like showers.

The dolomite may not carry any iron but rust stains that develop in this way are nearly impossible to remove so I wouldn't risk it.

Apply a sealer.

Choice of grout depends on the finish of the stone and the size of the grout line.

For honed or polished finishes you do not want to use a sanded grout or else it can scratch the finish. So use "unsanded" grout or epoxy for a smooth finish natural stone tile.

However, for tumbled or other rough finishes it is common to use a wide grout line (like 3/8" to 1/2") and sanded grout. Sanded grout will fill the grout line better and creates a stronger joint.

Thinner grout lines (1/8 inch or less) should use "non-sanded" grout.

I'm guessing your dolomite tile is either honed or polished and you'll be using thin grout lines (less than 1/8").

So... you should use non-sanded grout.

What about epoxy grout vs. non-sanded grout?

You could use epoxy grout, but it is more expensive, harder to work with, and looks a bit plastic.

But it does not need sealing and, generally, is water and stain-proof.

Limiting water absorption is not a big issue. Of course, you don't want water getting under the tiles, but that won't be a problem if the tile is installed and grouted correctly.

Regular cementitious grout has been used forever to limit water penetration without any problems so long as you clean it and take care of it. And that is not difficult. And you'll be sealing it, so no worries.

In a dolomite tile shower you'll still want to use a marble-safe cleaner. Dolomite can etch like marble so this Soap and Hard Water Cleaner for marble is perfect for a regular shower cleaner.

Non-sanded grout is easy to keep clean when cleaned regularly.

And yes... seal the grout while sealing the tile.

No matter what grout you choose you are going to apply a sealer to the tile after it is installed. So, you are going to seal the grout by default. It will be impossible to not get sealer on the grout and pointless to try.

Even though an epoxy grout doesn't need sealing, it won't cause any problems to apply the sealer.

The same is basically true of non-sanded grout, but it is a bit porous so will benefit some from the sealer.

Epoxy grout for marble floor tile
by: Sarah

Hello, after reading this article we are going to use a porcelain tile with marble look for our shower floor and then install the white Carrara marble on the bathroom floor.

We should probably still seal the marble floor, correct?

We are having our installer use epoxy grout, it's my understanding that this doesn't absorb water, is that correct? Thank you very much for this informative article!

==== Countertop Specialty comment:

Yes, epoxy grout is essentially waterproof and far more difficult to stain than standard grout.

Yes, you should apply a sealer for granite & marble to the Carrara marble floor tile.

Sealing a Carrara Marble Art Mosaic
by: Jano

Great information, site-wide. I've been scouring the internet for information about sealing and grouting an art mosaic I just finished.

It is made from varying sized pieces of honed white Cararra marble. The largest is 2" x 2" and the smallest 1/4" x 1/4" (the majority are these).

Besides the honed sides, many of the tesserae have riven faces, some quite rough. It is set in white Thinset.

Whether or not I grout the piece depends on what I find out.

1-Is staining unavoidable because of the rough riven and honed surfaces (as opposed to polished)?

2-Can some sort of impregnator/ sealer/ release be used prior to grouting in order to avoid staining the tesserae?

3-If yes, would it make sense to just immerse all the cut pieces in sealant before assembling the image? Or would this affect grouting?

4-Same answer whether light, neutral, or dark grout colors used?

5-Any reason to seal after grouting? I assume it would darken the grout, but there is no traffic, use, or exposure to the elements except dust.

==== Countertop Specialty comment:

I'd go ahead and seal the mosaic prior to grouting if using a darker-colored grout. Or wait and seal it all after grouting if the grout color is basically the same as the tile color.

Sealing can definitely help prevent staining even on riven surfaces. But you still have to clean up messes in a timely manner.

Sometimes the wet grout can absorb into the tile edges causing a dark ring around the tile. Sealing prior to grouting can prevent this. But this is usually only an issue with darker grout.

And immersing the tiles in a stone sealer is an efficient way to do it. And no it won't affect the grout once the sealer is cured.

But you don't really want to let the sealer just dry on it's own on the tiles. It could leave a hazy residue. On a honed or rough surface this may not happen, but it would be a real pain to fix if it did.

In this case, maybe it's best to seal the mosaic tiles prior to grouting but after the tiles are glued down just to be safe.

You could then make sure to wipe off any sealer residue before it dries.

It may also prevent any oxidation (rusting from exposure to water in the grout) of iron deposits often embedded in Carrara marble.

Because of these iron deposits in white marble you definitely want to seal white marble if it will ever be repeatedly exposed to water (like in a shower or outdoors). Applying a stone sealer will prevent rust stains.

But if it will just hand on the wall or something, then no real reason to seal it after completed.

How to seal grout in herringbone marble bathroom floor
by: Pamela

We are remodeling master bath with Carrara marble 12x24 tile on walls and herringbone tiny tiles (lots of grout lines) on floors, including shower.

All polished Carrera marble. My question is, should I seal all that grout in the floor? Best sealer? How?

==== Countertop Specialty comment:

The article above gives you the answer to this exact question.

Since it is Carrara marble (a white marble) it can contain embedded iron deposits and you need to seal both the tile and the grout in the shower.

Sealing prevents water absorption which can oxidize the iron deposits creating rust stains in the marble which are very hard and often impossible to remove.

How to seal the grout and tile?

By applying a sealer. A stone sealer (see the above article for recommendations) will seal both the tile and the grout.

It's not a complicated process. Directions are provided on the sealer bottles, etc.

Apply the sealer to the Carrara marble tile and grout by creating a film of sealer. Let it soak in for 2-5 minutes. Then wipe off all excess until completely dry.

For the walls, you'll have to spray on the sealer and wipe around with a paint brush or sponge to keep the tile and grout wet with sealer long enough to soak in. Then again, wipe completely dry.

Do not let the sealer dry on the surface or you'll get streaks that are very difficult to remove.

Help! Installed White Porous Marble for Steam Shower!
by: Arlene

A steam shower expert has just told me that I will have to tear apart my shower/white iceberg marble if we want to have a steam shower that will not "rot and mold."

Unknowingly we did not install the shower pan all the way up the walls and ceiling or a vapor cover and we don’t want to have this huge expense of tearing up the marble in order to protect from mold.

Ours is 5/8" and pretty porous so I fear he may be right.

He said there is no hope but I was hoping a sealant would do the trick?

Will this sealant you like protect the behind the shower (wood in walls) from humidity if installed and sealed correctly or is it just for preserving from stains and more on the surface issues etc?

Instead of tearing out all the marble installed we are considering aborting the steam component all together.

Thank you for all your help!

==== Countertop Specialty comment:

The main problem is not the marble tile but that you don't have the vapor barrier or shower pan needed for a steam shower.

The marble itself is not the problem. He may be a steam shower expert but possibly he does not know marble.

Everyone thinks marble is "stains" easily and is super porous. Well, this myth has been created because people confuse two different issue with marble as if they are the same.

Marble "etches" easily which is a chemical burn from acids and many cleaners. People think "etching" is the same as "staining" and conclude that "marble stains easily" and therefore, must be very porous.

Not true. Etching and staining are two unrelated issues.

Marble does NOT stain easily and is NOT super porous. It is actually quite dense. Yes, it is porous and can stain, but not to the extreme everyone thinks.

Water will not readily pass through the marble tile itself into the wood studs and wall creating a mold issue. Many steam rooms and showers are made with marble tile.

In other words, water does not saturate and leak through marble tile just from a single shower use. It would take hours of constant water exposure for the tile to become saturated with water and pass moisture out the back side into the walls.

And marble shower tiles dry out in between uses.

The grout lines are much more vulnerable to water penetration. This is usually how mold issues begin in showers with or without steam. Cracks in grout allow water behind the tiles and mold develops.

Now, if the steam shower was constantly used, then it is possible the marble tile could become saturated. So, it is important that the shower can effectively dry out between uses.

You should apply a quality sealer to white marble in the shower to prevent rust stains. White marble has embedded iron deposits that can rust from water exposure causing stains on the marble.

Sealers are designed to help prevent liquid absorption and possible staining.

So, yes... sealing your steam shower will help prevent moisture penetration into the tile and the walls, but no... it is not specifically designed for that purpose. Sealers are used primarily to prevent stains in the marble tile.

And again... grout joints are the weak spot for water penetration... not the tile.

Sealing the grout will help but it's cracks and voids in grout that usually are responsible. And poor ventilation. it is very important that the shower dries up quickly after use. Standing water is the main culprit for mold growth.

White Carrera marble shower
by: Brendan

Hey there loved the article. Best one I could find on sealing. My wife and I are about to put in white Carrara marble for our shower.

We performed the water test and found the marble to absorb some water within 5 minutes.

We were planning to use the SenGuard pro sealer that you recommend.

How many times should we apply the sealer to our marble?

Should we be worried about the fast absorption rate?

Could that be a sign of low quality marble?

Thank you!

==== Countertop Specialty comment:

Absorption rate is not a ranking factor for good vs. poor quality marble. Color, pattern, and integrity of that particular marble (or granite or any natural stone) is what determines quality.

Sure, it is better to have a low or slow rate of absorption but that doesn't speak to the quality or durability of the stone.

And 5 minutes isn't that fast so I wouldn't be worried. And it's probably honed marble which is more absorbent than a polished finish.

Some granites will absorb in under a minute. And some will take over 30 minutes to absorb. But 5 minutes is common and easily managed and improved by applying a sealer.

How many coats of sealer are needed

One may be enough and almost certainly no more than 3 will be needed.

-- Performed the water test prior to sealing.
-- Apply the first coat of sealer... wait 2 hours...
-- Perform the water test again
-- Note the improvement in time to absorption

The water test should take longer for the water to absorb after a coat of sealer. If it takes more than 15 minutes after the first coat, then I'd say you're good.

If less... apply a second coat... water test...

Water should take even longer to absorb after the second coat.

But when the time to absorption does not increase from one coating to the next... then you know you are done and additional coats will not improve protection.

Sealing White Dolomite Polished Marble
by: Anonymous

Hi, Great article! Thanks for all the valuable information for a marble novice.

We're currently installing white Dolomite polished marble for our shower walls and honed Carrara marble on the shower floor.

What would be the best method to apply the sealer on both areas? Any advice would be greatly appreciated. Thanks.

==== Countertop Specialty comment:

For the floor... pour on a little sealer and spread around with a paint brush to create a thin film over the entire surface.

For the walls... it's a bit more difficult, but walls are less susceptible to stains and water penetration. Use a spray bottle to apply the sealer also trying to create a thin film for the stone to absorb.

Spray on and then use the paint brush to spread around if needed.

Of course, you need to let the sealer absorb for 3-5 minutes, but then wipe all excess off and buff dry completely. Don't let sealer dry on the surface or you may get streaks.

Steam shower sealing
by: Craig

So, I have a steam shower and tile with 12 x 24 Malan gray marble honed tile and also 4 x 6 white Carrera honed and was wondering should I seal the tile or not seal the tile?

==== Countertop Specialty comment:

Well, a steam shower is harder on the tiles and will wear on the surface more than a standard shower.

Typically, you do want to seal Carrara marble and any white marble as iron deposits embedded in white marble can oxidize and cause rust stains.

So, I'd recommend to apply a sealer but you should also test the stone for absorption every year or two to see if you need to seal again.

Again, steam just wears more on the stone if it is heavily used and may require more frequent sealing. But just test to determine when or if it does.

Beige tile around a shower
by: Anonymous

I have a one piece shower/tub unit and am in the process of installing Queen beige amalfi marble subway tiles on the walls around it. The tiles cover roughly two feet of wall between the top of the shower and the ceiling as well as the surrounding walls to the floor.

The guy at The Tile Shop where we purchased the tile said we should seal the tiles before and after grouting. However I am questioning whether this is the best move after reading this article.

I’m completing the work myself on weekends, and as this is the only shower in my house it’s not possible to let it totally dry out for 2-3 weeks after installation.

I have not grouted yet but have the tiles covered to protect them from any little bit of potential splashing water, and hopefully from condensation from any shower steam (we vent the room when we have to shower).

In my situation, would it be best not to seal the tiles at all? The point of tiling was to protect the walls from shower steam etc but I’m concerned that if I seal them as recommended at the store I may cause a problem. Thanks!

==== Countertop Specialty comment:

Sealing tiles prior to installation or prior to grouting is typically only done when the grout color is a lot darker than the tile color.

The reason is to prevent the grout color from bleeding into the tile creating a dark "picture frame" around the tile edges.

But if you cannot let the shower dry out before sealing, then yes consider not sealing it or seal all tiles prior to grouting. Of course, that leaves your grout unsealed.

Usually, sealing a shower doesn't cause a problem. It's just not really necessary in most cases and can potentially lead to a greater problem.

More on Carrara Marble Shower
by: Donna

The installer said he would come by and have to "check a few things" to determine what’s wrong but insists the pitch he installed was on point.

He cannot return to inspect for a few weeks, will mold become a problem if we wait this long?

By the way, I did the water test you suggested and it’s fine everywhere else in the bathroom except the shower area where it gets absorbed.

If there was a way I could send you photos please let me know. Donna

==== Countertop Specialty comment:

If you don't use the shower and let it dry out then the mold will die off.

Note that we can only speculate at possible problems based on the info we are presented. The installation may be fine and something else is at work.

However, the difference in the water test between the shower floor and all the other marble is definitely a clue that your installer should consider when trying to figure this out.

You can send us photos via our Contact or Support forms. Click on this link, then on the next page click Contact Us at the top or the green Support tab on the right.

Honed Mosaic Carrara Thassos Marble Shower Sealing Problem
by: Donna

We just installed a honed mosaic carrera marble tile on our shower floors, and our entire master bath flooring. We ripped up the old shower floor and constructed the new shower with a curbless entry.

We installed a tile in linear drain and it’s gorgeous.

The installer instructed us to use 511 impregnate sealer on the floor prior to use.

We applied two coats on the shower floor area and one on the remaining floors which is also the same material.

After the 72 hour time frame, we used our brand new spa shower. A day later the shower floor was four shades darker than the floors around it.

Stunned and saddened as we noticed they didn’t go back to their "normal" dry color.

We stopped using the shower and waited two weeks for it to return to its normal state.

We were instructed by our tile installer to go over that area with two more coats of 511, which we did. We used the shower for the first time again yesterday, and nothing has changed.

The honed marble is dark again, and it doesn’t return to its normal shade.

We don’t know what to do except believe this is the nature of the stone?

The installer used shouter water proofing system and white thinset. Any suggestions would be appreciated.

==== Countertop Specialty comment:

Sounds like water is getting under the tiles. With a new install you shouldn't have cracks in the grout but there may be a problem with the plumbing, shower pan, or drain that is causing water to accumulate under the tiles.

Water can absorb into stone and then evaporate without issue. It will darken the stone, but then disappear once evaporated.

However, marble really isn't that porous to begin with and if it was properly sealed no water should be absorbing.

Two coats of 511 should have sealed it just fine.

The key seems that there was some delay in the stone darkening after use. If water was absorbing from the surface you'd see that within 30 minutes of use.

If it took until the next day to see it darken, then it is likely water is absorbing through the tile from underneath.

Spill some water on the bathroom floor outside the shower and see what happens. My guess is that it will take forever to absorb and darken (if it does at all). It is does darken it will quickly disappear (within a a few hours or less) as the water evaporates.

Try the same (let a puddle of water absorb) inside the shower for comparison. But the shower floor must be completely dry and back to normal color first. And don't let any water down the drain as this may be the point where water is getting under the tile.

Time how long it takes to darken the stone in both locations and note any differences to give you clues to the nature and source of the problem.

If the water test results are the same for both locations (i.e. takes the same time to absorb and lighten again) then the problem is likely water under the shower tiles.

Hopefully, it is not this problem because would likely have to rip out and reinstall it.

Good article
by: Anonymous

I’m preparing to have marble installed in my bathroom. After reading tons of articles about to seal or not to seal marble, this article explains best about what to do. Thank you for your information.

China Marble
by: Anonymous

I purchased Bianco Orion Polished Marble Tile for shower walls. I was told to seal prior to install. I have done that (511 porous plus), its not on the walls yet.

I was told to seal all sides of the marble.

Now I have read somewhere else the grout will not adhere to the sides of the tile. Have you ever seen where this would be an issue?

Do you have any idea if this type of marble has rust issues?

Also I have noticed the marble is from CHINA, do you know anything about marble from china? I never knew there was such a thing, but that is what I have and the cost was 50% less.

==== Countertop Specialty comment:

Sealing the tile prior to install and grouting is fine. Only really necessary if you are using a dark grout that could bleed into the stone and cause some darkening of the edges.

But the grout will still adhere just fine. No problem.

It is a white marble and many white marbles do have iron deposits embedded and can, therefore, develop rust stains if water absorbs and oxidizes the iron.

Marble from China is fine. Many natural stones come from China.

Black granite is the only one with any real issues as it can sometimes be "doctored" or dyed to make more black. This causes problems with etching.

Carrera marble tile on shower walls.
by: Anonymous

I have read your wonderful post and comments but want to clarify one thing... I only have beveled Carrara white marble tile on the walls to the top of my tub and ceiling.

I have good ventilation in the bathroom. Since I don't have any surface that water can stay, I am thinking of not sealing.

But what about the grout? Should I still use your product for grout?

Does grout dry and crack with age? Or should I leave it because if it gets wet then it can evaporate.

I don't mind iron deposits. It will go with my rustic bathroom. Thank you so much.

==== Countertop Specialty comment:

If you think sealing the marble isn't needed, then it isn't needed for the grout either. Sealing is done to prevent substances that could stain from absorbing into the stone or grout.

The iron deposits in white marble like Carrara marble can lead to large and irregular yellow-orange stains. Generally, not pretty.

This is the reason to apply a sealer to white marble in showers or around tubs where the marble will be regularly exposed to water.

Of course, if just a tub surround and the there is no shower so the walls will not be exposed to water much, then your risk of rust staining is much less.

Help, huge smears!
by: Anonymous

Great article, I have questions.. we had a wetroom both walls and floor tiles with beautiful marble.

The tilers were very particular and did s lovely job. But between tiling and grouting and then sealing the tilers told me to stay out of it until it’s sealed as I could stain it.

Hence I did as I was told, now since it has been ‘sealed ‘ and now fully operational I’m not happy with the finish.

In certain points where the light shines I can see huge smears the whole thing just looks dirty. I suspect this is because the sealant was applied over dust and dirt as I can’t no matter what I do get these smears off.

I know I’m not aloud to use abrasive cleaners so what do I do, does the sealant need to be stripped off and cleaned and start again or what do I do, please help.

==== Countertop Specialty comment:

It could be either grout haze (film of grout stuck to the tile) not properly removed or haze from sealer residue due to incorrect sealer application.

Both can look similar (chalky, dull) but grout haze will usually have a slight texture.

To remove grout haze use the Hard Water and Soap Film Remover which will remove the grout but is totally safe for use on marble.

Also, use this cleaner as your regular shower cleaner to eliminate film buildup that occurs in every shower.

To remove sealer haze, you'll need to scrub with acetone, which won't harm the marble. If acetone doesn't work, then you'll have to use a more potent solvent like methylene chloride (found in paint strippers). Also won't harm marble.

Sealing after rust stain removal?
by: Anonymous

I have polished carrera shower walls. Installed professionally about 1 yr ago.

After about 6 months, I noticed brown patches showing up in the carrera, which is definitely oxidizing iron deposits.

I am on vacation now, so letting the marble dry out for about 10 days.

Then I plan to remove rust stains with a poultice of Iron Out and baby powder. Fix any etching with polish powder.

My question is - should I seal with a permanent product (SenGuard)? I'm worried the rust patches might come back and then I wouldn't be able to remove them with a poultice if I've sealed with SenGuard.

I'm not sure how the water exposure occurred in the first place. I've inspected the grout and I've found only a few very tiny hairline cracks or tiny pin holes, but these aren't even necessarily near the tiles that have the brown patches.

I think the stone is somewhat abosorbent because I've noticed dark gray vertical lines forming when condensation droplets runs down the walls during a shower. I can't do the water drop test, though, because the stone is only on vertical surfaces.

What is meant by "faulty installation?" I've installed some tile myself before, so I know the main process. This marble was installed by professionals.

Should I seal after removing rust stains? And how do I keep them from coming back?


==== Countertop Specialty comment:

Yes, you should apply a stone sealer after removing the rust stains and fixing any etching.

SenGuard is your best option. Best protection and permanent bonds.

The rust stains can happen with repeated cycles of slight water absorption into the face of the tile. Problem is worse with cracks in grout, etc.

Showers don't typically require sealing, except white marble for exactly this reason. Grout can be perfect and can still get rust stains.

It won't happen in every white marble or Carrara marble shower, but not worth the risk. Seal it for sure.

The sealer will not prevent you from removing any future stains. The chance of additional rust stains after applying Senguard should be minimal.

The primary factor post-sealing would be the integrity of the grout. Make sure it's always in good shape and shouldn't have problems in the future.

Nemo carrara mosaic darker in "wet" areas
by: Anonymous

Hi there, we just had Nemo Ruscello tiles (small mosaic in honed carrara marble) installed in our shower floor and one wall. We asked the contractor to seal them as we were told to do so.

Now whenever we take a shower in it, the area where the water hit stays and looks wet and darker. Not the entire floor though, just the area where the water hit directly, both on the floor and the wall.

Any suggestion on how to deal with this? Thank you!

==== Countertop Specialty comment:

Probably the tile was not sealed or not sealed well enough and water is absorbing creating a dark spot that goes away when it evaporates.

Typically, this is not a problem, however, Carrara marble can contain iron deposits that can rust with repeated water exposure.

So, you need to make sure the tile is sealed properly.

Carrara Marble dull after grouting
by: Anonymous

Do you polish the marble before sealing. After grouting the tile looks dull.

==== Countertop Specialty comment:

If the tile is dull after grouting, then it is probably due to grout haze on the face of the tiles.

This must be removed, but careful what you use. Most grout haze removers will etch marble.

This Hard Water Remover for marble will remove the haze safely.

Once the haze is removed, you can apply the sealer.

And by the way... the Hard Water Remover is also the best cleaner to use as your "regular" shower cleaner.

Carrara marble turning gray
by: AnonymousCarole

I just had the basket weave honed Carrara marble installed on the shower and entire master bathroom floor.

I haven't even started using the shower or bathroom since it is still being renovated.

I already have noticed the marble turning dark gray just from them getting water on the tile from a sponge or spilling water from a bucket.

In some of the areas it take days to lighten back up. I'm really worried to see what will happen to the shower floor once I actually take a shower.

I'm concerned about sealing the floor in the shower area since it can cause evaporation problems but I don't want to risk getting iron oxidation of the floor.

What do you recommend I do.

==== Countertop Specialty comment:

In general, natural stone tile does not need sealing in the shower since the risk of staining is very low.

The one exception is white marble like Carrara marble precisely because of the iron deposits within the marble and potential for rust staining.

You must apply a sealer to prevent this. Applying a sealer to shower tiles is only a problem when water is getting behind the tiles. This can happen with an improper installation, or more commonly, when there are cracks or voids in the grout.

When the shower tiles and grout are in good condition the sealer will not cause any problems. It will simply keep water from absorbing to prevent oxidation of the iron deposits within white marble.

The iron deposit problem is not an issue with any other marble or natural stone color.

Marble tile will darken or turn gray when water is absorbed. This is normal. However, it should not take days for the water to evaporate and the spot to disappear.

If this is the case on newly installed marble shower tile, then I consider that the installation was not done correctly and water is getting behind the tiles.

Or it could be that the shower / bathroom does not have sufficient ventilation / air flow to promote evaporation.

Cream Beige Carrara Polished Marble
by: James

Howdy. Excellent article. If I may ask, is it white....and only white Carrara marble you recommend sealing, or would a "cream / beige" Carrara fall into the same category.

Our cream / beige does have hints of off whites intermixed. Thanks in advance.

==== Countertop Specialty comment:

"Carrara" marble can be different shades of white (some lighter, some more grayish, or slight hint of yellow), but usually is not anywhere close to "beige".

Understand that "Carrara" references a specific marble quarried from Carrara, Italy. It is a white marble (with grayish tones and blue / gray veining).

There are many cream / beige-colored marbles, but these are not "Carrara" marble.

So yes, it is only the white marbles (like Carrara, Calacatta) that contain iron deposits and should be sealed when installed in a shower.

Of course, if you like you can apply a sealer to your marble shower tile. It isn't a high-risk area for stains and is generally unnecessary, but won't cause any problems unless water gets behind the tiles.

Water getting behind the tiles will only occur when there are cracks or broken grout lines. In rare cases, due to a poor tile installation.

So, if your shower is in good condition, the sealer won't cause any issue. Just really not needed except for white marble.

Grout separation from natural stone shower
by: Anonymous

Thank you for explaining how to care for your white, off white in our case, stone.

Unfortunately, our shower is beyond the prevention stage, and has been exposed to water for over a year, and has turned orange-the grout being much worse than the stone.

A larger concern is the grout connecting the floor and the wall has pulled away from the wall, and water continues to get behind it.

I do not know how to proceed with preparing this area before moving on to the sealing.

I've considered using a chisel or dermal tool to remove the grout, or a portion of it, and then replace it, but am afraid I will make matters worse, or create a huge problem.

I am looking for an educated suggestion on how I should move forward with this project.

=== Countertop Specialty comment:

The only way to move forward with this problem is to remove the old grout. This shouldn't be a problem. You run very little risk of damaging the marble.

However, as you stated the marble has turned orange it may not be worth saving.

The orange coloration is rust staining.

White marble contains iron deposits. When the tile gets saturated these iron deposits oxidize and the rusty water moves to the surface and evaporates leaving the orange rust stain.

This type of rust stain is permanent. It is too deep in the tile to remove.

It sounds like you let this go far too long and, honestly, I'd seriously consider ripping it all out and installing a new tile shower.

But if you want to go with repairing this one, then you need to stop using it for a week or two to let it dry out completely. Water is likely trapped under the tiles and this needs time to evaporate.

Given your description of the current condition, I'm surprised you don't also have mildew everywhere.

Anyway... let the shower totally dry out. Then remove all the grout using a Dremel, chisel, or scraper or however seems effective. Then re-grout.

Wait another 2 - 3 weeks to allow the grout to dry and any remaining moisture to evaporate and then apply a good sealer.

Sealing honed marble shower floor against etching
by: Floyd

We have a newly installed hex mosaic honed carrara marble shower floor.

The shower went unused for a good 3-4 weeks from install before we started using it. We unknowingly used some cleaners that produced a few etch marks before reading up on the proper care of marble.

Our tile guy said we could use any kind of cleaner, bad advice. Anyway, I bought some etch remover and the proper cleaners for stone and I also want to seal the marble to prevent future etching or iron stains because the stone is soft and more absorbent than polished marble.

My question is, how long should I let the floor dry after showering or cleaning before I apply the sealer?

==== Countertop Specialty comment:

Since you let the tile and grout dry out real well for 3-4 weeks after install you won't have to wait so long this time.

That is assuming the installation was done well, grout is all tight with no cracks or voids that could have allowed water to get under the tiles. Most likely everything is fine, but just letting you know the variables.

I'd let the shower dry for a week prior to applying the sealer.

But note.... a sealer will prevent stains and water absorption that could lead to rust stains from the embedded iron deposits found in Carrara marble.... however, sealers won't prevent etching.

Etching is physical damage to the marble. It's like a burn. So, expecting a sealer to protect against this is like expecting car wax to prevent a scratch in the paint from a key or some other hard object.

Etching in a shower 99% of the time is due to use of the wrong harsh cleaners (which is most common cleaners) to clean the marble.

You should use the Soap Film / Hard Water cleaner as your regular shower cleaner.

This product is specially formulated for use on marble, travertine and all natural stone without any damage or etching. And it is super-effective cleaning the films that are the biggest problem in showers.

So, fix the etch marks, seal it (I recommend SenGuard Sealer) and then clean it with the right product and you won't have any more problems.

Sealing To Prevent Rust Stains White Marble Shower
by: Anonymous

I have a white marble shower saddle that was sealed. Then they installed the shower door with a stainless steel screw.

The screw hole rusted and we have to replace the saddle. We don't want this to happen again.

Should we be sealing after the shower door is installed? It seems like water will always get down the screw hole.

==== Countertop Specialty comment:

Yes, this could be a recurring problem unless you find a way to seal off the screw hole from the marble. I know stainless steel is not supposed to rust (in theory) but it still does under certain conditions.

You should be sealing inside the screw hole, but this won't completely stop a rust stain from developing.

I'm sure the screw hole is collecting water that just sits there oxidizing the metal. The rusty water then eventually absorbs into the marble.

Note that a sealer cannot absolutely prevent absorption. Sealers dramatically slow down absorption, but don't completely prevent it.

If the water sits long enough the marble will absorb it even when sealed.

I think the key here is that all parts used to install the door must be 100% stainless steel (not just plated), but then if possible, caulk around the screw hole to prevent water collecting and remaining around the screw.

even water can't escape gravity
by: Anonymous

The wall grout where the water bounces off of the person showering will soak up enough water to be pulled into the edge of the tile by gravity.

A simple test would be to towel off those areas after showering. If the water didn't penetrate the grout then it should not remain dark from the water, if it remains dark then the water has penetrated the surface of the grout and gravity will take it from there.

=== Countertop Specialty comment:

True, grout is porous and will absorb some water. However, it is not a sponge and the amount actually absorbed (especially on a wall) is minimal, at the surface only, and will evaporate before it does any real damage.

Gravity may take it into the stone or the stone itself may absorb some water when showering, but again... it's only at the surface and so minimal that it will quickly evaporate without leaving a trace. And this repeated process can go on for years and years without any issue, damage or staining.

It's only when significant amounts of water get behind the tiles and grout that staining and damage occur. And significant amounts of water don't enter unless via cracks and voids or poor installation... not from surface absorption.

Now if the shower had really bad ventilation and never dried out, then I'd agree that even the minimal surface absorption could become a problem as more water is added with each use of the shower. Certainly, you'd have a mold / mildew issue but could also get staining and other damage to the tile and grout from the constant water exposure.

Sealing statuary white marble shower tile
by: Anonymous

Thanks for the article. It says polished marble does not absorb much so sealing in the shower is not necessary. Then there was a comment from the site recommending sealing a polished Carrara marble in response to another person's question.

Should you seal polished statuary marble inside a shower? Or floor as well? Thanks so much!

==== Countertop Specialty comment:

You may have missed the section about "exceptions" to sealing marble shower tile. White marble is the exception since it can contain iron deposits that can cause rust stains with repeated exposure to water.

So, yes.... you should seal statuary white marble shower tile even when polished.

It is true that polished marble can be nearly non-absorbent so the risk of rust stains on a polished (vs. honed) marble is lower, but white marble in a shower is the one case where it is beneficial to apply a sealer to a low-absorbency stone.

Rust stains from embedded iron deposits are basically permanent, so you want to do everything possible to avoid them. Just be sure to apply the sealer correctly and do not allow it to dry, wipe off all excess after absorbing and then wipe the marble completely dry and buff out any streaks.

You didn't mention the grout
by: TS

A customer of mine pointed this article/blog out to me, I am a stone restoration professional with 10 years in business.
I agree with most of what has been said in this article, and it it very refreshing to see that there is some "Real" advice out there as far as sealing natural stones goes.

The only thing not mentioned was that the grout is very porous and will soak up water even on the walls. Remembering that the edges of the tiles that the grout is up against is rough cut and not finished like the face of the tile, this makes it tremendously more porous, thus the need for a sealer to guard against water intrusion through the sides of the stone (like was mentioned with the grout color penetrating through the sides).

I have seen marble showers where the water soaked in through the sides and down to the lower tile and a half, making the appearance of fish bowl waves.

My only point is that the grout will be porous no matter what the tile is.

Very good article, just my two cents. I can tell by the products that you recommend for maintenance on your site that you are very knowledgeable about how to care for your stone, keep up the good work!

==== Countertop Specialty comment:

Thanks for your input! Yes, grout is porous, although, when properly installed water absorption is not an issue.

The amount of water absorbed during a shower is minimal and will quickly evaporate.

When water does cause damage it is nearly always because of cracks, voids or faults in the grout (or from poorly installed tile / grout) allowing a much higher volume of water to enter and get behind the tile. This is especially true on walls where water never has a chance to pool.

When water gets behind shower tiles it will not evaporate quickly and will start to cause damage or consistent mold issues, etc.

And when the tile and grout have been sealed the evaporation of water behind the tiles is slowed even more. Even though modern stone sealers allow the stone to breath, it is not the same as an unsealed tile and water behind a tile is effectively trapped.

For the above reasons, it is unwise and unnecessary in most cases to seal stone or grout in a wet environment (except for white marble tile showers).

But also, it is very important to routinely inspect grout lines for cracks and voids. Allow the shower to dry out thoroughly and make needed repairs in order to maintain the long-term integrity of your shower tile.

Cream Colored Travertine Shower Walls and Bench
by: Mike

Hi! Thanks for your valuable info! Should we leave our cream colored travertine subway size tile on our shower walls and bench in the shower as is or follow the same rules as the white marble? Thanks!

==== Countertop Specialty comment:

Travertine shower walls are at virtually zero risk for staining and the "white marble" issue doesn't apply so no reason to seal the walls.

The bench you may want to seal only because water and other products left over from showering or from leaky bottles set on the bench, etc., could cause a stain.

Still not too big a risk on the bench, but probably the most likely place in your shower (along with shelves) to get a stain and easy to seal it.

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.

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.

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.

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.

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.

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.

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.

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

by: Alvaro Castellanos

very good article good description

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