Tile FAQ’s

The list below contains some of the most commonly asked questions I get about tile and installation methods. For each one I have included a (very) short answer.  I already have, or will have in the future, a post about every one of these. If that post already exists there will be a link at the end of the answer.

I will continue to add to this page as the questions come up. If you have a question just leave a comment at the bottom and I’ll include it on this page.

Just click on the question to view the answer.

Grout

What type of grout should I use for my tile?

It depends on the tile and the size of the grout lines. Read this: Using the correct type of grout

How large should my grout lines be?

It depends on the tile size and the look you want. Read this: How large should grout lines be?

Can I fill my cracking grout with more grout?

Maybe. Read this article for a more complete answer: Filling grout lines with more grout

Are there any “magic” products available to remove stains from your grout and tile?

No there are not. One of the closest things to magic that you can buy is oxygen bleach. It is not bleach! It's a slight misnomer. This is the main ingredient in products like oxyclean. It works very, very well to clean grout. More information: How to clean grout

Does grout help stabilize tile, hold them in place, or make them stick better?

No it does not. (Epoxy grout is different) Read this: Does grout stabilize tile?

Are tile, stone or grout waterproof?

No they are not. Read this: Is tile waterproof?

Can I install my tile without grout lines?

No, you should not. Read this: Tile with no grout

Miscellaneous

Can I install floor tiles on my shower walls?

Yes you can. Read this: Floor tiles on a wall

Sealers

Will sealing your tile and grout make it waterproof?

No! It absolutely will not.

Should I seal (or re-seal) my tile and grout?

If you would like it to be easier to clean then yes, you should.

Setting Materials

What should I use to set my tile?

It depends on where you are installing the tile. Read this: Proper setting materials for tile

Are mastic and pre-mixed “mortar” acceptable to install tile on a floor or in a shower?

No they are not. Read this: Proper setting materials for tile

Substrates

Does my floor have to be level before I install tile?

No it does not. Read this: Does my floor have to be level for tile?

Do I need a waterproof membrane for my shower walls?

Yes, a membrane of some sort is required. Read the article for the different types. Read this: Preparing a shower wall for tile

Can I simply stick tile to the drywall in my shower or the plywood on my floor?

You can but it won’t last – so no. Read this: Preparing a shower wall for tile or this: Installing backerboard for floor tile

Transitions

Should I use grout or caulk in the corners of my shower?

Technically? Caulk. Realistically? It depends. Read this: Caulk or grout in corners?

If you have any suggestions or questions please feel free to leave a comment.

mark

Hi Roger Any opinion on Schluters new product for heating tile floors Ditra heat?

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Roger

Hi Mark,

Yes! My opinion is that I will never do another heated floor without ditra-heat mat. :D I still use the suntouch wires in it (voids my warranty – I’m a rebel like that) but the mat that you lock the cable into is a VERY good product.

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Roger

What format are the ebooks? Can you get hard copy, or only ebooks?

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Roger

Hi Roger,

They are pdf files. I only have the files, no hard copies (the prices would be outrageous).

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kathy

Hi Roger,

I bourght non-vitreous tile (water absorption >7%) and I just read on the Home depot site that this is not appropriate for tub shower walls. Has a PEI of 0.

I believe you said on FAQ that this is not an issue unless it goes in freezing conditions.

I’m getting 2 different answers. What do I do?

Reply

kathy

Oh I forgot — I’m using Durock and Redgard in the shower per your booklet.

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Roger

Hi Kathy,

You’re getting different answers because there a bunch of things mixed up here. Non-vitreous tile is just fine for tub shower walls. As long as your shower walls are properly waterproofed then you could install sponges for wall tile and it won’t be an issue. It is only an issue in a steam shower or outdoors. The PEI rating indicates that it is only for use on walls with no foot traffic. Unless you’re married to spiderman this shouldn’t be an issue. :D

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chris

Roger — thanks for all of your help!! Could not do it without you.

I am debating how high the tile goes up the wall in the tub shower – either about 3/4 up the wall, which seems to be the standard or all the way up and on the ceiling up to the sliding tub door.

1.) What do you think is best?

2.) If I do the 3/4 up plan, can I Durock the entire wall and ceiling in the tub area, redgard and then paint over the redgard on the Durock smooth side at the top part of the wall and ceiling?

Reply

Roger

Hi Chris,

1. I go all the way to the ceiling.

2. You can durock the entire wall, but you can’t paint over redgard. It won’t stick. You can prime and paint durock, though.

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chris

Do you tile the ceiling in the shower area too?

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Roger

Sometimes, not very often, though, unless it’s a steam shower or has a header across the entrance.

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chris

Hey Roger,

I think I screwed up again. I realized that the first 3/4 ply that I screwed down to the joists in my bathroom is cabinet grade S2S and MAYBE NOT exterior grade.

Some of the screws going thru the 1/2″ exposure 1 ply on top into the 3/4″ cabinet grade were not grabbing/countersinking and I’m thinking it’s because the 3/4″ is soft. (too soft as a subfloor maybe?)

I’m screwing Durock thinsetted with Versabond on top of the 2 layers of ply. Topped with 2″ marble mosiac.

1.) Is it possible that the 3/4 is not rated exterior and will cause a problem if water gets thru? There’s no other rating info printed on the wood

2.) If I silicone caulk and thinset/mesh the floor to wall Durock corners and wall to wall Durock corners and Redgard everything (tub shower) as outlined in in your booklet, am I ensured of no problems?

3.) Do I have to rip the whole thing up now?

Reply

Roger

1. Yes, it’s possible.

2. You are never ensured of no problems. :D That said, doing that would be your best option and would protect the ply if it is not exterior rated ply.

3. No.

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chris

Thanks, that’s good to know.

1.) do you think the cabinet grade ply might too soft for a floor?

2.) How often do you have screws just spin when flush and not counter sink when screwing 2 layers of ply?

Reply

Roger

1. Yes

2. Never.

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Neil Garber

I just installed 1/2 Durock in my alcove and it sits 1/4 inch below the old plaster wall. I was considering just putting some 1/4 inch Hardie over this to bring it out to the same plane. I can’t think of why this wouldn’t work. It’s too late to pull the Durock and shim the wall. That would involve a divorce lawyer. Thanks for the help.
Neil

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Mark

Roger:

I just installed 18″ travertine, sealed with Miracle 511 for grout release and then applied Miracle Seal & Enhance after grouting. My wife would like things to be a bit shinier still. The Miracle High gloss finish sealer is not recommended for honed travertine but I’d just as soon not buy a buffer and doom myself to continued applications of floor polish. Do you have any suggestions?

Thanks,

Mark

Reply

Mark

Roger:

Never mind. The Miracle folks have informed me that nothing will stick to the Seal & Enhance coating. They recommend using the Limestone and Travertine Soap and buffing it a bit. Sorry to add unnecessarily to your workload.

I used a lot of your advice in planning and installation. It was a great help. After 1700 sqft though, I wonder how you can do this for a living!?! It is a task….

Thanks anyway for your help.

Mark

Reply

Roger

The end result is worth it! That’s the only way. :D

I did not know it wouldn’t stick. Good to know, thank you.

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Roger

Hi Mark,

The high gloss is not recommended because of the pore size of travertine. Being that you’ve already sealed it once with the 511 you can use the high gloss on it, it should be just fine.

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Jennifer

Hi Roger,

We are in the middle of a tile job and the contractor had to remove some of the tile he had already installed over the last couple of days. My question is whether all of the thinset has to be removed before he relays the tile … there is Ditra underneath the thinset, and I don’t see how he would be able to remove the thinset that filled in all of those orange squares. If he can scrape the thinset off so that it is at the same level as the top of the Ditra, will that suffice? Also, can he reuse the tiles he had to pull up, or should they all be new, untouched tiles? Many thanks for your help!

Reply

Roger

Hi Jennifer,

I doesn’t have to be removed from the waffles of the ditra, level with the top is fine. The tiles can be reused if they are not damaged while being removed.

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chris

Roger is all home depot plywood exterior grade as in suitable as a bathroom subfloor? I got BC sanded 3/4″ — there were no markings

Reply

Roger

It is technically supposed to be AB grade, but that is normally fine for a bathroom floor.

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chris

How do I know it’s exterior grade?

Reply

Roger

The letter ‘X’ denotes that the glue bonding the layers is rated for covered exterior use. As in CDX – it is CD rated plywood with exterior grade glue.

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chris

I really screwed up and used Custom Simple Set premix thinset to apply my floor Durock backer to the plywood. I guess it’s best to read directions BEFORE using a product.

This is a 5′ by 6′ bathroom floor. How hard is it to remove the backer once the screws are removed? I have a heavy duty hand held hammer drill with chisel attachment. I know I have to get the wood smooth but how cleaned of thinset residue should it be before using a polymer ­modified mortar to re apply new backer? F——-!!!!!

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chris

what’s the best product to use to re-apply backer to 2 plywood layers erroneously glued and screwed? I can use Home Depot or Lowes.

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Roger

If you mean thinset anything in a bag you mix with water will work fine.

Reply

Roger

It shouldn’t be that difficult at all. And you don’t need to get the plywood totally flat or clean to bond the thinset, it doesn’t need to bond. It’s only there to fill voids beneath the backer.

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chris

Do you think it’s ok to leave it with the Simple set bonding backer to the ply floor?

Reply

Roger

No. If it gets wet it will emulsify and create more problems.

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chris

Roger,

On applying 1/2″ Durock to my bathroom floor, is it OK to counter sink the screw between 1/16″ and 1/8″?

How close to the eges of the Durock do I need to put the screws — I’m afraid to break off pieces at the edges. Is it OK to stay 1 to 2″ away from the edge?

Second question is should I thinset over the scews to make the screw indentations flush bebore applying Redguard, like you would with drywall?

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Roger

Yes, 1/8″ or less countersink is fine. Within 1-2″ is fine as well. It is easier if you skim over the screws first.

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Deena

Hi Roger, An apprentice did the grout work for my new rectified tiles and it looks horrible! He even used a darker color grout than he was supposed to! Even my builder agrees that the grout needs to be redone. Does ALL the grout down to the backer board need to be removed to redo the job properly? Or can some of the grout remain? In other words, how deep do you have to go to remove the grout, especially since a lighter color will be used in the re-work? Hope this is clear. And what is the proper tool to use to remove the grout and not damage the new tile? Thanks so much, Roger!

Reply

Roger

Hi Deena,

The existing grout needs to be removed down to at least 2/3 the depth of the tile. You need a grout saw. There are several variations.

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Will Jackson

Dear Dr. Elf,
Fantastic site; many thanks for valuable humor. Oh, and good information too.
Setting Marble 12×12 floor tiles over properly installed hardibacker etc.

Simplify for me; marble/travertine/stone specific thinset or don’t sweat and use thinset thinset?

Many thanks.

Reply

Roger

Hi Will,

If you have a proper floor built and you have consistently sized marble a good thinset will work just fine. Mapei ultraflex 2 or laticrete 254 will work perfectly.

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Oystein Rogne

Hello floor elf.

I decided to tackle a tile project myself. I expanded my patio and laid tile on top of concrete. I researched a bunch online and got lots of advice.
Anyway, the tile is down. It looks ok. Some flaws I admit.
I used the polymer reinforced thinset and my question is: some areas of a few tiles sound hollow when I tap my finger on them. Not the whole tile, but part of it. Sounds like a part of the tile is not adhering?
I have not grouted yet.
Short of ripping up the tiles that seem to be “loose” how can I fix this??
Will the grout aid in adhesion? /fill under the tile??

Reply

Roger

Hi Oystein,

Are you sure there’s anything that needs to be fixed? A lot of things can cause a ‘hollow’ sounding tile, it doesn’t necessarily mean it’s not bonded properly. If you push on the corner of the tile does it move at all? If it isn’t bonded you will see a little flex in it. No, grout will not help. It will initially, but it will eventually grind away if your tile is moving. It will fill in the area and be fine if your tile is not moving, though.

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Oystein Rogne

I am not positive. Most of the hollow sounding tiles only have a smaller area that sounds hollow, like a corner. They don’t seem to move much.
A couple have a larger area that sounds hollow, and seem to move just a bit.
Some people suggested this fix-a-floor adhesive. Since I haven’t grouted yet, do you think forcing some of this under the tiles might do the trick?
Thanks again

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Roger

It might. That’s just an epoxy setting material, you can do the same thing with thinset. :)

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Mike

Roger,

I have heard that “high-end” showers have their walls floated. I believe this to mean that the walls are skinned with joint compound to get them as true as possible. Can you comment on this?

Reply

Roger

Hi Mike,

It is a full mud shower. The walls are created and formed with wet mud rather than a solid board substrate. Once it cures the tile is bonded directly to them. They are bomb-proof and laser flat when done correctly. And not all high-end showers are done that way. That’s what I build and I’ve only done mud about five times in the last five years.

Reply

Paul

Hi Roger,

Getting ready to install some tile on our remodel shower. Picking out the tile and all the pieces is getting to be a project on its own.

We’re having some problems with the the shower curb and coming up with something that would work. The curb is a Schluter curb 6 X 4.5 inches X 5 feet. All the bull nose and other pieces aren’t working out with the tile selected for the shower. We’re trying to stay away from a grout line down the middle of the curb.

I’d really like to cut the large wall tiles and install them on the curb but then the problem of the exposed edges comes up. My question, how much work is it finish and polish the edges of a marble tile cut to fit the curb? The curb is 60″ long so we’re talking about 120″ of polishing for the top of the curb. I have a hand grinder but I’d like some feedback from someone that may have already done this.

Reply

Roger

Hi Paul,

Polishing marble takes much more equipment than a grinder. My polishing equipment cost is right up around $1000. You can do it with varying grits of sandpaper, but you’ll never get a ‘factory’ look on the edge without wet-polishing it. But it can be done.

Any particular reason you don’t want a grout line down the middle of the curb? If you have a matching bullnose (difficult to tell from your statement) you can always put the bullnose on the sides of the curb and use a cut full tile on the top.

Reply

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