Up until about two months ago, I would've told you to definitely seal it. But it just so happens that right now I'm having a big problem with discolored Calcutta Gold marble on a shower floor, and depending on who you ask, the sealer may or may not be to blame.

Let me also say this-- years ago, I had a master bath in my own home that was marble throughout. Not a bit of stone in that bathroom-- either in the shower or out, ever saw a drop of sealer.

how about the grout? the grout has to be sealed, right?

Sorry to hijack....
I'm about to have honed calacatta hex installed in my bathroom, including the shower floor. Is the discoloration more typical of a polished finish because of the reaction of the sealer on the polish??? Or should I ask my installer not to seal it? I can't see how it's possible to seal the grout in a 1' hex without sealing the tile anyway...
Thanks!

{{gwi:1410762}}

This is white Italian Marble and it received 3 coats of sealer. Look at the water bead. A solvent based sealer has smaller particles than water based sealers and will seal deeper into the stone. Aqua Mix is my preferred sealer of choice. Always test your sealer and inspect the results before jumping in feet first.

Some of my biggest tilling mishaps have resulted in learning proper installing techniques and proper dwelling times. Much better to go slow and steady and do the job in 4-5 coats than 1-2 heavy ones. Keep a bunch of lint free rags with you and read up on this procedure from multiple sources before starting.

We have made it a rule since last summers "Enrich n Seal" disaster that a test board be made for every job and that the grout and sealers all installed prior to setting tile. This test board can aid in tile layout and allows the client to see the grout installed and dried and what the sealer looks like finished.

I think marble in a bathroom is timeless but it comes with caution. Iron content and other strange "Tile Fairy" issues come up and there is always a chance you may need to replace some or all of a natural marble installation.

If you don't like these risks, do extra testing, buy better tile from a better supplier or switch to porcelain.

Here is a link that might be useful: Aqua Mix - Ultra Solv

so here i am again...kinda too late for the above. my marble hex tiles are in, grouted with unsanded grout. the guy told me he'd have to probably apply more grout since the unsanded tends to shrink. looks like it did already. so my question still stands: does the grout get sealed?

If you're going to seal the grout, then you're going to seal the tile, as well. With stone, no two ways about it. In spite of my (soon to be past) experience, It's a good idea to seal the stone. I would NOT use a water based sealer, as John has suggested, though. You want one that will allow vapor transmission back and forth, so that moisture can't get trapped.

bill, thanks so much for your response.

last night i was reading as much as i could on different sites. i came across one site that there is a generally rule of thumb to determine if you should seal your stone. they said to spill water on it and wait about a half hour and see if the stone darkened. i did that on some leftover tile and fell asleep. woke up 7 hours later and the water was still pooled on top of the calacatta hex tile with no discoloration or darkening. do you still think i shoud seal?

It sounds like it may already be sealed. All marble should be sealed. No exceptions.

ok, thanks. but back to the grout question. from what i've been understanding (i think)is that you seal grout to keep it clean, or to help it from staining. at this point the tile is down and unsanded grout has been in for about 3 days and has shrunk somewhat. the tile guy knew that would happen and said he'd regrout. can you regrout over it? also, does that powdery stuff from the grout ever stop rubbing off? since you suspect that the tile has already been sealed would it hurt to apply sealer for the sake of the grout?

Thanks for this thread. My master bathroom floor is a basket weave marble and I am at a stage where this advice was a necessity. After reading here, I asked the tile person if our marble floor was going to be sealed. He said the builder & floor place had not budgeted for it or ordered it done. My floor isn't even a polished marble.

at this point the tile is down and unsanded grout has been in for about 3 days and has shrunk somewhat. the tile guy knew that would happen and said he'd regrout. can you regrout over it?

Best I can say is he'd better get it done FAST. My rule of thumb is usually 72 hours. He's just past that now. if he doesn't get it soon, you may have a problem with the second coat of grout flaking off. He could have avoided the problem by mixing the grout super stiff-- then it wouldn't have shrunk as much, if at all.

also, does that powdery stuff from the grout ever stop rubbing off?

No, you'll be cleaning that till the day you die. :-) (just kidding) it stops pretty quickly after installation.

since you suspect that the tile has already been sealed would it hurt to apply sealer for the sake of the grout?

No, but be sure to buff off as much sealer as possible off the face of the tile, so it doesn't haze up on the face of it.

jolynna-- Not a problem. This isn't rocket science. I'm the same way-- I leave the sealing to the homeowner, normally, because it's not hard to do, and it'll save them alot of money in the time I would have to charge for. Take an old terrycloth towel, tear it in two. Use one side to apply the sealer, and the other side to wipe off the excess after a couple of minutes.