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.

Paula

Hello,
My gout is in perfection condition, however it is too low. It is the kitchen floor and it impossible to mop, the grout never gets clean unless I scrub it. It is too much work. How can I even it out?
I know you wrote that new grout will not adhere, is there a thick paint I could use?
Thanks

Reply

Jeremy

Hi Rodger,

Installing travertine over Schluter membrane in the shower. What type of thinset is preferred, unmodified or modified?

Thank you.

Reply

Paul

Poured substrate mud on floor leveler on concrete after reading your article. Sorry, I can not leave it alone. Sounded substrate and found a 6 to 8 inch circle that sounds hollow. It is about 8″ from drain. All mud beaten down with 2×4 just like you advised.

Question, should I worry enough to break this hollow sounding area back out and pour again??????

Reply

Roger

Hi Paul,

NO!!!! Leave it alone. Really. It’s fine. :D

Reply

Kim

Tiling the bathroom floor..does tile go underneath the toilet flange or level with top of flange

Reply

Roger

Hi Kim,

Ideally under it, but it can go level with it as well.

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hal

Roger – I think somewhere I screwed up on my Kerdi drain. I cut the drain pipe 2″ below the surface of the floor. When I put the Kerdi drain on and mate it completely, the flange sits a little more than 1″ off the floor surface (the foam spacers are about 1/4″ above the floor). Should I cut the drain lower to get the 3/4″ mud thickness or should I just pack mud under it anyways and raise the entire floor? If I raise the entire floor, how close can the mud deck be to the top of the curb? I hope it was something simple I missed. Thanks

Reply

Roger

Hi Hal,

Provided your floor is at least 1″ lower than the top of the curb (unless your local codes require more) then you can just pack mud under it. 3/4″ is the minimum (the height off the floor with the spacers), it can be bigger than that by however much you need.

Reply

Hal

Thanks Roger – What do you do if the drain pipe isn’t perfectly vertical? I can’t get the drain level and it tends to “spring back” to an unlevel position. I’m worried that once I pack under it, and then glue and mortar it down, it will want to spring back to a unlevel position. How do you do this everyday?? I can’t even handle one bathroom!

Reply

Roger

Hi Hal,

Once you pack the mud under it really well it won’t go anywhere. Really. :D I don’t know how I do it every day either.

Reply

joe

Hi Roger -again thanks for all the help. whats the procedure for using hydroban on durcock in the corners and seams ? do I just apply to fiberglass tape one coat at a time? or do do I thinset over the tape and then apply the hydroban ? Thanks again

Reply

Roger

Hi Joe,

Tape and mud the seams normally, let that cure, then install the hydroban over it.

Reply

Victoria Holbrook

How do I lay a diagonal running bond tile pattern? I wish to tile the entire house with this pattern. The tile I have selected is poreclain 18 x 18. Do I start at the front door, go down the hallway and into the adjoining kitchen and living room? Or do I start in the middle of the largest room and flow into the other areas? Thank you, this web site is the best for the DIYer.

Reply

Roger

Hi Victoria,

I dunno, I can’t see your house from here. :D Layout, especially in something that large, requires a lot of time and thought. When you are tiling that much it is not imperative to begin at the front door. You need to measure out everything and shift the layout around to find what fits best for all the rooms. A diagonal running bond is identical to a straight running bond. It’s just turned 45 degrees. :D

Reply

Blayne

First off, thanks for all the info you have on this site, it really helps a ton. I am building my shower in a new constructions home. THe shower is roughly 5×4. There 36 inch door opening that goes up about 7 foot and the shower ceiling is 9 foot. In the ceiling of the shower there is green drywall. The rest I took out to replace with cement backer board. My question is do I need to remove the green drywall on the ceiling and replace it with cement backer board? I am going to put tile on it.
My second questions is regarding the material used to create a moisture barrier between my cement backer board and wall studs. I had a roll of Titanium UDL-30 synthetic roofing underlayment that was left over from covering the roof (not the felt stuff, its basically plastic with metal grid lines in it). (http://www.interwrap.com/titanium/udl_30_fb.html). I put it up over the shower wall studs as the moister barrier. Will this be ok?

Reply

Roger

Hi Blayne,

Yes, you need to remove the greenboard. Since you have a header across your shower with a closed ceiling you will have a lot of vapor getting up in there, greenboard isn’t the product you want behind your tile. I am not familiar with the udl-30 you mentioned but from the link you provided I don’t see any reason why that wouldn’t work just fine.

Reply

Sharon

If tiles and grout are not waterproof then why the heck are we using grout? Is it just to look purrty :lol: yeh pretty

Reply

Roger

To fill the spaces between the tile. It’s better to have grout in there than mold, yes? :D

Reply

Michael

Hi Roger,
Have you every used the Boost product for grout?
I understand that instead of mixing the grout with water, you mix it with Boost to make it stain resistant.
Thanks,
Michael

Reply

Michael

Hi Roger –
OK – I ‘m replying to my own question (don’t you hate that).
In further reading on your site – you discuss epoxy grout. Sounds like this is the latest technology. My tile supply store has Mapei OptiColor epoxy grout. So I’m thinking I’d go with that.
My only hesitation is the removal of the ‘haze’.
Is the haze with epoxy going to be hard to remove?
Thanks

Reply

Roger

If you clean it properly as you are grouting you won’t have any haze at all. Haze is not a given, it’s a by-product of incomplete or improper cleaning of the grout off the face of the tile.

Reply

Michael

Thanks Roger –
Here’s another question – you had some info on sealing around the openings in the wall for the shower valve, etc. (unfortunately I can’t seem to find that info anymore now that I’m up to that step).
I was thinking of using a Schluter product with a rubber ring, but you had shown the option of sealing with silicone caulk (I think) behind the tile. Any info appreciated here.
Thanks -

Reply

Roger

The kerdi rings work well, but you can also do it with silicone.

Reply

Roger

Hi Michael,

Yes I’ve use it. I don’t like it. It does what it says it does, I just don’t like how the grout feels when I use it. It works differently. It works, though.

Reply

joe

I’m installing a tileredi polyurathane pan for my shower which has a 1/2″ wide return which the durock sits on. they also give you an aluminum “z” flashing to put on this ledge. Manufacturer recommends epoxy for the wall tile coming down into the pan. I’m installing 12 x 24 marble tile on wall with thinset. Won’t the thickness of the thinset push the marble tile too far out from the epoxy on the pan wall ? Any thoughts would be appreciated, thanks much for your time.

Reply

Roger

Hi Joe,

You need to either have the wall substrate flush with the sides of the pan, thus using epoxy and thinset on the same plane, or the wall substrate completely down over the vertical sides of the pan down to the lip, using thinset all the way down.

Reply

joe

Yes I understand but what is the minimum thickness of thinset required on the durock wall to hold 12 x 24 marble tile ? I’m thinking that thickness will be so much more than the thickness of the epoxy holding the bottom half of the same tile. Thanks for you help.

Reply

Roger

Use the same size trowel and you’ll have the same thickness. I’m unsure what the issue is? Perhaps I’m just not understanding the problem. The minimum thickness of thinset required behind tile is 3/32″. The proper thickness of thinset behind the tile is whatever gives you the proper coverage.

Reply

joe

Ok thanks for getting me straight. I will try a thickness closer to 3/32 and go from there. Much appreciated,take care.

Reply

Mike

Heylo, Roger. Love your site. So, I was all excited about using Ditra under porcelain in my bathroom, but I couldn’t put the Ditra right over the vinyl (or linoleum…not sure what the hell I’ve got here, so I’m going to keep calling it vinyl) because the vinyl’s peeling up in some places, and I’ve read that if that’s happening, the vinyl should come up before the Ditra goes down.

Anyway, of course there is vinyl adhesive all over my OSB subfloor, and Schluter says “absolutely not” (I called them) to installing Ditra on top of the glue. They said there may be some kind (was driving, so couldn’t write it down) of self-leveling thinset that can go on top of the adhesive, and that once it cures, I could go over that thinset with the modified thinset to bond the Ditra. That sounds a bit nuts, so I’m looking for other options, preferably not as nuts-sounding.

In your expert opinion, what are my options? Replace entire subfloor? Abandon Ditra and go with Hardiebacker (will I run into the same issue)? Scrape as much of the glue away as possible?

Any advice would be greatly appreciated. Thanks so much.

Reply

Roger

Hi Mike,

The easiest would be to get 1/4″ backer and go over the glue with thinset and the backer. You can then either tile directly to it or use ditra over that.

Reply

Craig Goodman

I have a question about how to finish the tile on inside corner joints. Can I butt the tile up tight to the adjacent tile face or do I need to leave a space for expansion? I do not anticipate that there would be atmospheric expansion with tiles.
I prefer the look of the tiles butted tightly together.

Reply

Roger

Hi Craig,

You do need to leave a minimum of 1/16″ for expansion. Porcelain can actually expand up to 1.5%.

Reply

Hal

Hi Roger,

I’m installing a Kerdi drain in my shower. When I ripped up the cement and old plastic drain, there was a 6″ dia hole in my subfloor around the drain. I believe I know the answer already…do I need to cut out a section of my subfloor and install a new piece so I can have a proper sized hole for the Kerdi drain?

Thanks

Reply

Roger

Hi Hal,

Yes, but you already knew that. :D You can also just add another piece of ply over it about 1′ square with the hole drilled in the middle of it. If you use 1/2″ it will give you the correct height around the perimeter of the drain.

Reply

Dan McDermott

I need to install a neo angle shower enclosure that reequires at least 3 holes on each side to hold the frame to the walls. These holes will be about 3/4 inch (1 inch max) from the end of the wall tile.

What is the best procedure to drill a hole in these ceramic wall tiles so they do not crack in the future or during the drilling process?

Reply

Roger

Hi Dan,

I use a spade bit (they look like little arrows) to drill through them. If installed correctly they will not crack in the future, once drilled that’s all the stress the tile should be exposed to.

Reply

Jerry

Hey there, great site. I have installed tile for many years and from time to time run across this problem and condition in old mud installs on restoration projects. Some of the lower courses of tile come loose ( sometimes only a few) for one reason or another and the rest of the tile field is solid. They are usually antique tile and are irreplaceable, and the customer just wants them reinstalled. ( maybe they need a tear out and rebuild but they don’t want that route) The problem is that reinstalling the tile with thinset will always pronounce the tile from the original field. Although acceptable under the circumstances, I was wondering if you have come across this problem and do you have a suggestion for reinstalling the tile that I might have missed. A product that will work in a wet install? thanks J M

Reply

Roger

Hi Jerry,

I have run across it. What I do is chip out about 1/8″ of the mud wall to that part of the wall is inset. Install the tile with a good modified thinset and it should be flush with the existing tile. Epoxy setting material usually works as well, but without chipping out the substrate it’s difficult to get flush. Those installations are normally wet-set, so you don’t have the buffer layer of old thinset behind it to remove, you need to do that to the substrate instead.

Reply

Marcel

Roger,
Finally, I managed to build the preslope for my small (3′ x 3′) shower (over a concrete slab). Seems very solid but it is not nice and smooth.

I tried to make it smoother by sanding it w/ coarse grain sandpaper.
Unfortunately, that made it look even more uneven, with many 1/16″ to 1/8″ deep irregularities.

Can/Should I fix the pre-slope, i.e. make it all even, with a layer of thinset over the sanded surface?
Thanks,
Marcel

Reply

Roger

Hi Marcel,

Yes, skimming it with thinset will smooth it out and fill any small inconsistencies.

Reply

Kerry

Roger, help please…
We just had one of my husband’s friends install tile in our bathroom floor. We were told he has done a lot of tile work so we let him do our floor, as a favor to us (the labor price was right…. free). Our bathroom (second bath) has been down to the studs for 2 years due to the remodel budget going to medical bills instead :( so we were kind of desperate. The problem is he apparently never used a level and it is a mess! Tiles are all uneven, major “lippage” – the floor is only 4′ x 7′ but there are probably 5 or more (1 ft sq tiles) in the center that are way out of wack! It hasn’t been grouted yet luckily but we know we will have to break the tile to get it up and start over, but here is the problem…. We have heated mats under the tile! Is there a way to salvage the heated mat or will we lose that as well when we tear up the tile/thinset from the concrete board? If it is possible to save it how would we do that? They are the mats that have the wiring woven on the orange grids for easy installation. Any suggestions? I appreciate any ideas you can send our way…

Thank you!!!

Reply

Roger

Hi Kerry,

It will be slow but once you pry up the first tile you can take the flat side of a crowbar and pound it right along the underside of the tile. If you have sufficient thinset covering the wires you should be able to chip it off without damaging the wire.

Reply

Emmy

Hi Roger,

I am installing a tile tub surround. The homeowner put up the backer-board himself. It is a white cement board that I am not familiar with. I have only used the grey, rocky mesh type cement board. The board he installed has a smooth side and a rough side. He installed it with the smooth side out. We are installing 9×12″ ceramic tile with thinset mortar. Will it work with the smooth side out or was it meant to be hung rough side out?

Thanks!

Reply

Roger

Hi Emmy,

There are many backers with a rough side and a smooth side. It normally makes no difference which side is out. I have never, however, seen a white one.

Reply

Emmy

That makes me feel better that you have never seen white either! I was feeling ignorant. I will find out where this was purchased and get more info about the product before I begin any tiling.

Reply

Roger

I was just informed by another reader that it may be from menards, which would make it the finpan board (it hasn’t always been white). If it is indeed finpan then it’s just fine. That’s a good product.

Reply

Diane

I am a DIY type, and laid a floating plank cork floor myself throughout the downstairs. I decided to treat myself and have cork mosaic “penny” tile installed in the powder bath/laundry area by a “professional”. I wanted SO bad to stand over them and make sure each sheet of circles was placed “just right”. I refrained from doing so, and treated them as professionals. They assured me that I would be happy with their installation job. The attention to detail did not happen. The spacing of the tile is poor with some of the circles touching with no grout, and others with large gaps which “jump out” like a bold line. They told me that once it was grouted, I would not notice. WRONG! It is even more apparent. It has now been grouted and sealed. Is there any going back to fix this? I think some of the places could be chiseled out, and possibly centered, but at this point I wonder if an area rug is my only answer. They have not been paid yet, so at a minimum I am going to reduce the agreed amount. Is that legal?

Reply

Roger

Hi Diane,

Whether it is legal or not depends on your contract and your local laws. I can’t see either from here. :D If they look like that then they’ll need to be removed and replaced properly. Depending on how bad it is that may require as little as just the offending ones or as much as the entire floor. Tell them they are not getting paid until you are happy with the work provided.

Reply

Renee

Can I install a prefabricated kerdi niche if I’m also using the traditional shower wall procedure ? The contractor is building the shower using the studs, then moisture barrier, then backer board method. Thanks!

Reply

Roger

Yes. You’ll just need to silicone the moisture barrier to the back of the backerboard around the opening for the niche.

Reply

Renee

Our contractor is using the traditional method, but I checked out the progress today and I don’t know if we’re going to have a problem. It looks like there’s green board butted up next to the tile edge (bullnose isn’t installed yet so I’m assuming it is going on top of the green board. The green board extends to the floor of the shower stall. I tried uploading pics on your upload page — not sure if it was successful.

Reply

Roger

Hi Renee,

I don’t see any photos, however, if he has greenboard INSIDE the shower (any part of it) then it is not done correctly. The backer can butt up to it, but it needs to be outside the wet area.

Reply

Corinne

in my tub and shower I am tiling to the ceiling the ceiling is green drywall do I need to water proof this? I live in a trailer and have 7ft ceilings. And what do I put on that joint where the cement board meets the drywall? 8)

Reply

Roger

Hi Corinne,

You don’t need to, but with shorter ceilings like that it is always best. You need to tape and mud that joint.

Reply

Corey

Hi,
Can I install Red Guard on Durock if there is a plastic
moisture – vapor barrier on the studs behind the concrete board?
Thanks

Reply

Roger

Hi Corey,

You need to have one or the other, not both. And posting twice doesn’t get an answer faster – day job and all. :D

Reply

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