There are three basic materials used to set tile.

  • Mastic
  • Thinset Mortar
  • Epoxy

For each installation there is a specific material you should be using. Before you start any tile installation you should ensure that the material you choose is suitable for that application.

Mastic

Mastic is a latex or solvent based adhesive that cures by evaporation. It is sold in airtight containers (buckets) and requires no mixing. It is ready to use immediately. It is suitable only for non-wet applications.

Mastic should never be used for showers or floors! Ever! When mastic gets wet the water will re-emulsify the adhesive base. This means that mastic turns to goo when it gets wet. Goo will not keep your tiles on the wall. Every one of the failed showers that I’ve ever replaced were installed with mastic.

With that said typed, mastic does have its place. It is “stickier” than thinset mortar which is why some prefer to use it – for everything. It should only be used in non-wet areas such as a backsplash, wainscot, or fireplace. An area that is not consistently exposed to water or moisture. It should also only be used on tiles smaller than 6 inches square.

Think about it like this: mastic is stored in a bucket with a lid on it. This keeps it from being exposed to air which would cause it to cure (dry). If you spread it on your wall and place a 12 X 12 inch tile on it, that’s just like putting the lid back on the bucket. It will never fully cure. If any moisture gets behind that tile with the mastic it will eventually re-emulsify and lose adhesion. That means is that your tile is going to fall off the wall.

There is also a product called “premixed thinset adhesive”. This product is pushed as a suitable material with which to set tile – it is not. It is only mastic with sand added to it. While sand does help materials from shrinking as it sets, it does not make mastic suitable for showers or floors.

Thinset Mortar

Thinset mortar is what you need to use for shower walls and floors of any type. It is sold in bags and needs to be mixed with water. Sound simple? It is. Referred to as thinset, mud, mortar, or a number of other things, it is a combination of sand, portland cement, lime, and other stuff that makes it the preferred setting material for elves everywhere.

When mixed properly (read the directions, no, really, read the directions) it is stable,  not compromised by water or moisture, and rock solid. Thinset must be mixed with water, allowed to slake, then remixed before use. Slaking refers to letting it set for a specific amount of time to allow the chemicals to interact and become workable.

Thinset cures through a chemical process, not by evaporation. Air is not required for it to set. It will cure in the bottom of a bucket of water, really. This means that no matter the density or type of tile you use it for, it will fully cure. No worries there. The tile will stay where you put it.

Unlike mastic, thinset will not be compromised by water or moisture. If it gets wets the thinset will remain cured and will not be reactivated. It’s similar to your driveway. The concrete on your driveway was mixed with water but it doesn’t turn to mush when it rains. It’s the same stuff.

Thinset mortar will be the correct setting material for nearly every application.

Epoxy

Epoxy is a chemical based glue that cures through chemical interaction. It is almost bulletproof and not user-friendly. To be frank, it’s a pain in the ass. It is usually a two or three part product which, when mixed together, form a very stiff, very thick putty-like substance. When cured it becomes a permanant part of whatever is attached to it. That’s great on the back of the tile, not so much if you get it on the front. Use with care, it is nearly impossible to get off of anything once it’s set.

There are not many applications which require the use of epoxy setting materials. Certain exterior applications need it, swimming pools, certain types of stone and glass tiles. While epoxy can be used for any application, only specific jobs actually require it. It’s expensive. I mean really expensive. If you don’t need to use it, don’t.

If you are unsure whether or not your product or application requires epoxy, just check the manufacturer’s recommendations. If it is required, they will make sure you know about it. You can also ask me, just leave a question in the comments. I’ll reply, I’m a fairly sociable guy when I’m not crawling around on a floor.

Which to use

The general rule of thumb is to use thinset mortar. Unless your specific application requires epoxy, thinset can be used. Anywhere you can use mastic you can use thinset instead. It is more durable, water resistant, and cheaper than mastic anyway. As far as I’m concerned, the only thing mastic is good for is a free bucket.

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  • robb

    Hi .Im replacing a few white marble tiles on an exterior wall that have cracked /chipped along the bottom .the base is a sponge like material the thickness of the tiles(1/2″)im guessing so the tiles arent sitting on the concrete sidewalk. the tiles are adhered only to about 1 1/2 to 2 inches above grade and the adhesive is gapped only about 1/8′. my questions are will i be able to use a non sag thinset at this thickness ?the package describes use from3/16″ to 1/2″ comb also what is the lowest temperature i can work this application (not indicated on package) and will thios thinset be affected by rain? and if so what time period before any significant rainfall should be observed?
    )

    • Jason Huggett

      Hi, Robb,

      I replied to your question through my email. Let me know if you did not receive my replies and I will post them on here, sir.

      -Jason Huggett

      • Jason Huggett

        Just in case you did not get my replies, and in case this may help someone else who has a similar question, here were my replies to you, sir.

        Hello, Robb, thanks for the question.
        I hope I understand your question correctly, sir. Before I get started, I would like to add that if the material you are sticking to is “spongy” (or moves when you push on it), you will need to cut that out (whatever the material is, and replace it with something else. Hardibacker is the best, TRUST ME on this one.)

        The temperature is typically not recommended below 70 degrees. Although, if your in a bind, its worth a shot if it’s colder than that. I would personally give it a go.

        You most certainly will want to use a WHITE thin set. If you have cracked tiles already, as you mentioned, that means that there has been some type of movement in the past.

        Note: one thing to remember; tile must ALWAYS have a SOLID place to be stuck to. No exceptions!

        I prefer to upgrade to “flex bond”, although it is more expensive. In my area, Flexbond runs around $25 a bag.

        Flexbond is designed to actually “flex” a little, allowing for movement, and helping to avoid/prevent cracking that is due to movement. But don’t worry, just because the thin set is designed to flex, it is not at all a softer material than other thin sets. In fact, it is MUCH MUCH harder. I do not understand the technology behind this scenario, so I can not explain that one.

        1) If the wall needs to be built out, do one of two things, sir. Either skim coat the surface, allow it to dry and then install your tile (or skim coat again until you reach your desired thickness. I have had to go beyond the recommended thickness before, and I did not have any issues. But, if you have to build out on a wall too thick, the thin set will possibly ooze out from the bottom, gravity’s a pooper sometimes.

        2) Use Hardibacker to build out before you stick the tile. If you still need to build out more, you can always use a shim on the studs before installing the Hardiboard (or whatever backer board you decide to use).

        Here’s a cool tip that I picked up along the way. If you do not want to buy more backer board and “double rock,” cut the board into a few strips and install those to the studs-then install your backer board on top of that.

        Finally, MAKE CERTAIN that you skim coat the back of your tiles with the flat side of your tryle before you butter them. Doing this does a few things, especially for marbles. One, it will, for lack of better terms, “seal” the back of the tiles, eliminating any bleed-throughs of other materials, such as dirt, for example. It also insures that the tile gets a proper adhesion and strengthens the back of the tile, which makes the tile much stronger. Much like how grout bonds the tiles of an area together.

        Anyway, sir, I really hope this helps you! I also hope I got back to you soon enough, and answered all your questions. If there is anything else I can do for you, I’d be glad to help.

        Have a nice day,
        -Jason Huggett

    • Jason Huggett

      Hello, Mr. Robb, I hope you received my reply to your question, sir (I replied from my phone). If you didn’t get my reply, let me know and I will resend it.
      I think I left part of your question unanswered. Sorry about that. If you are referring to a “saggy” thin set because of the tile sliding down once you stick it, use nails or prop something (anything, like a stick or a 2×4, rocks, etc.) to hold it in place while it dries.
      Take care! :^)
      -Jason Huggett

      • Roger

        Hey Jason,

        Thanks for the help! I don’t mind anyone else answering questions but I really prefer you do it as a reply to their initial question rather than email. (As you’ve already done). This helps both with making sure they receive their reply as well as keeping everything in the same thread so if I come in later and answer a second question I know what they’ve been told, what they’re doing and how to answer it. If it isn’t there we need to start from the beginning. It also assists anyone else with the same question as you’ve stated.

        Thanks!

    • Roger

      Hey Robb,

      Everything Jason stated is accurate, if your substrate behind the tile is spongy. If it’s just the base portion beneath the tile that’s spongy then it’s fine. Most non-sag or medium bed thinsets are good only up to 1/2″ and that’s pushing it in my opinion. I would either do as Jason suggested with the layers or install a 1/4″ layer of hardi behind it. Thinsets are best over 70f, but I’ve used them down to 55f or so. A 24 hour period without rain will be fine, so long as you are not in a freeze-thaw environment. If that’s the case then you need a full 28 days cure.

      Another possible option for you would be a quickset thinset. It cures anywhere from 1 – 5 hours depending on which you use. I recently used laticrete’s 4xlt rapid and it is some absolutely awesome thinset. It may be just the ticket for you – it’s non-sag as well.

      • Jason Huggett

        Howdy again, guys. I have been meaning to get back on here and comment, I have been out.

        Anyhoot, I wanted to add as a cheap alternative to the $30 speedsets. You can get a bag of the cheap stuff (or any thinset) and just add some baking soda to it. Not a lot, a little will do, and the thinset will dry within 30 min. The more you add the faster it will dry, so be carefull, or you’ll be mixing a new batch in 30 seconds.

        Did you ever fix your problem, Robb?

        See ya, :rockon:

        -Jason Huggett (the Tile Mechanic)
        “If you love your floor, you gotta Huggett!”

        • Roger

          Yup, it will. And all my reps absolutely lose their minds when I tell them I’ve done it with one of their products. :D

  • Jason Huggett

    Hello, Mr. Roger.
    I stumbled across this website, and I think that is awesome, sir!
    I have been a tile man for 15 years, specializing in hard-surface restorations (i.e. Mexican tile refinishing, repairs, acid washing, etc.).
    I found your disapproval for mastic somewhat intriguing. Although, I completely agree with you that thin-set is the absolute best go-to! I wanted to add a couple of comments to your post on mastic, if I may sir?
    Adding to your reasonings as to why people use it, I must admit, it beats the snot out of mixing (meaning that it is often used for sheer laziness, and yes, I too am guilty of this). And I loved your comment on using mastic to obtain a free bucket (HAA!). Too funny! :^)
    You mentioned back buttering the pieces; I just wrote a comment on another website discussing this matter. This step is usually skipped on the majority of installs, but one who would skip skimming the back of a stone such as travertine should, in my opinion, retire his or her knee pads for a paint brush.
    Epoxies- I remember when the epoxy grouts first came out. Luckily, I never had to use them, and I do not see them anymore. I have also never seen the epoxies that you mentioned for installing, another positive point for me, it sounds like! I am in Texas, perhaps the epoxies haven’t made their way here yet, or possibly I have purposely passed them by.
    Replacing showers- I have never had a problem with the mastics (on walls) as far as the reasoning for needing to replace a shower. Typically, the showers that I replace due to malfunction are due to a leaking pan.
    When I was a green setter, I used mastic to build out a row of tile on a wall (float or whatever one wants to call it) and that stuff NEVER dried! Yes, I did end up having to replace it on my own expense, rookie mistake. My take, mastic is okay for walls as long nothing needs to be floated (or built out). I have used mastic on many countertops as well. I have one tub surround, and countertop that I installed in my home about ten years ago; they are both still going strong (although, time to update, in my opinion).
    That premixed thin-set that you mentioned- I can sum that up in one word, JUNK!
    I had one pro tip for tearing out shower pans in less than ten minutes that I wanted to share, and mud work the like, and then I will shut my trap.
    Using a chipping hammer, score the pan, or mud walls (whatever you’re tearing out) just as if you were scoring a ceramic on a cutting board. Using straight, up and down motions to make the score, just keep making the motion. For example, in a 3×3 shower, make a + sign in the mud with your chipping hammer. Often times you can go right through the tile. However, if the tile is too tuff and takes a lot of effort, remove it first, also by using the chipping hammer. After you have scored the mud work, pick a spot along the score line and jab the bit of the chipping hammer that you are using down into the mud (with the chipping hammer on), slowly working towards an angle from a straight starting point.
    Once you have penetrated the mud, and you reach a point that you are able to have the hammer at an angle, with the hammer still running, pry the mud work apart by using the chipping hammer as a pry bar (don’t force it, go slow and allow the hammer to do the work for you, that’s what it is for) (it will not bend or break the bit or the hammer) and the pan will break into four large chunks, much like cutting a tile on the cutting board. This method works for all mud work, although for larger areas, do not try to make your score lines too large. When working on walls, start at the top and the weight of the mud work will help pull off the rest of the walls (below the section that you are working on).
    I hope this helps anybody who is dreading a tear out coming up. Many guys I have worked with in the past didn’t believe that it works, but it does, see for your-self. If there are any other tips that I can give for tear outs or repairs of any kind, please feel free to ask, I love helping.
    Last tip of the day- let any advice that the guy working at Homedepot gives you go in one ear and out the other. Asking the guys at Homedepot how to do something; is like asking a car salesman how to change your transmission!
    Have a nice day! :^)
    -Jason Huggett

    • Roger

      Hey Jason,

      That method does work well. Of course what works better is hiring someone else to take it out. :D

      Thanks for the tips.

  • henry

    Hi

    I am hoping you can shed light on this. I have a 12×12 tile floor in my upstair bathroom installed new a year ago on a plywood subfloor. I have radiant heat between the floor joint. In the summer I realized that a lot of the tile were loose. I removed a couple and saw that almost all of the mortar stuck to the subfloor but not to the tile. The installer tells me that this is unheard of. He is proposing to fix this by leaving the mortar on the subfloor and re-gluing the loose tiles with epoxy…. your comments would be appreciated. Thanks.

    • Roger

      Hey Henry,

      The problem is not only the lack of coverage on your tile (they obviously were not back-buttered when installed), the main problem is that the tile is installed directly to plywood. Without in-floor heat this is an issue due to normal expansion and contraction in the plywood – thinset will only compensate for so much. The in-floor heat exacerbates the problem. Epoxy will not solve it. Epoxy is actually brittle – strong as hell, but brittle. The expansion in the plywood will pop it loose just like it did with the thinset.

      The best solution is to have either a self-leveling cement poured over the heating elements, then tile installed directly to it, or kerdi installed over it and the tile installed to it. The tile needs a proper substrate, it doesn’t sound like that is currently in place.

  • Inga

    Three weeks ago I had 9×18 white marble tiles installed around my tub walls.
    The thin set used was dark grey in color and my white marble tiles turned grey. I was told by the tiler that the thin set would take two weeks to dry and for the marble to turn white again!
    After three weeks the tiles are a little lighter in color but not the White Bianca luna marble tile color I had intended.
    Are there different colored inset cements on the market?
    Should the tiler of used a white cement?

    • Roger

      Hi Inga,

      Yes, white thinset should have been used. Is the darkening throughout the entire tile or is it just around the edges? If just around the edges it’s due to water being absorbed by the marble while grouting, we call it picture-framing. It will dissipate, that can take up to a month. If it is throughout the tile it is due to the thinset and the only solution is to replace the tile. White marble should always be installed with white thinset specifically for that reason.

  • Barrie

    Roger, about 12 one inch square tiles have come up from my shower floor. I have been using a 15 minute quick dry cement that says its stronger than regular cement but within 2 to 3 weeks the cement wears away and the tiles all come back up. They are all located around the shower drain. can you please tell me what type of cement i need to get and how to use it. thanks, Barrie

    • Roger

      Hi Barrie,

      You need powdered thinset which is sold in the tile section. You mix it with water (follow the amount on the bag) and cover the floor beneath the tiles you are replacing and place the tile into it while it is still wet. Let it cure overnight and they should stay in place for you.

      • barrie

        roger , thank you for such a quick reply. just one question, following your instructions . at what point am able to remove excess off the tops of the tiles. im am assuming the thinset will cover the tops of the tiles. at what point can i wipe away the excess that will cover the tops of the tiles. ps this problem has been going on for over a year and your the first to give the correct advice. my hat goes off to you. thanks again. Barrie

        • Roger

          You need to use grout after the tile sets, that is what fills in the grout lines. The thinset is just to bond the tile to the substrate. It’s a two-step process, you don’t want thinset on the top of the tile. You’ll mix the grout up and fill the lines, let it sit for 20-30 minutes and clean it off the face of the tiles.

  • Shang

    Hi Roger,

    Doing a small 36×36 stall shower. The base is built up wood/drywall due to a basement install using an upflush saniflo toilet pump.
    The P trap is underneath the built up base.
    I’m using ditra membrane over the drywall along with the ditra drain.

    Can I use un-modified thinset to build up the base for the 1/4 per ft preslope? Do I have to use the bed mud at 2in thick? I’m trying to minimize the height due to low ceiling and the elevated base from the p-trap.

    The drain is already below the surface of the floor in the stall so the layer does not have to be thick to get my slope. I was planning to put the ditra over this thinset bed.

    Love the site!
    Thanks,
    Shang

    • Shang

      opps! I ment kerdi membrane? I have ditra also for the floor in the rest of the bath.

    • Roger

      Hi Shang,

      You need deck mud, thinset will crack and, in turn, so will your grout. You can start with 1 1/4 inches thick around the perimeter and run it down to the drain at 1/4″ / foot. That will be thick enough to not crack and support your tile installation.

  • Kim

    Thank you so much!! I didn’t expect a quick response, I really appreciate it!!

  • Kim

    I have installed wall tiles in my bathroom and am getting ready to put a mosaic border above those tiles, followed by a travertine liner. Should I use thinset to apply liner? It will be directly on wall resting on mosaic border. I am also a little concerned about it squishing excess from the top. This will be the most decorative piece in my bathroom. Any info is appreciated. Thank you.

    • Roger

      Hi Kim,

      Yes, use thinset. You can use a v-notch trowel with notches smaller than the thickness of the tile. You can also put the thinset on the wall and flip the trowel over to the flat side and knock down the ridges so you have a flat layer of thinset on the wall, without ridges.

  • Gary

    Roger,

    Thanks again, I’m getting it from Tiles redi. I have one more question, is there any thing other than water or something to add with the water to the thinset to help the tiles stick better to the walls. I’m using 13″ tiles on the tub and shower walls.

    Thanks

    gary :wink:

    • Roger

      You can mix it with the admix for the specific thinset. Or you can use a non-sag thinset, which is sticky.

  • Gary

    Roger,

    Thanks for the answer. I have a couple of niches which come from the same place but they don’t send epoxy with them. Also incase I have problems getting the epoxy from Tile Redi does Homedepot or Lowes sell a epoxy that I could use?

    Thanks

    Gary :shades:

    • Roger

      Neither sells an epoxy setting material. You’ll need to order it online from somewhere unless you have a tile supply shop around you. I’ve never had any problem getting replacements from tile redi, though.

  • Gary

    Roger,

    I installed a Tile Redi shower pan and it shipped with laticrete 300 epoxy. One of the three part mix had a leak in it. I was wondering did I need to use a epoxy on the this shower pan or can I just use the same thinset that I will be using on the walls on the shower pan?

    Thanks

    Gary

    • Roger

      Hi Gary,

      Thinset will not bond to it long-term. You need the epoxy. Call tile-redi and they’ll send you another epoxy unit.

  • Monti

    Hey I’m glad I found you– I’m doing a mosaic table commission – the table is going to sit outside exposed– there is a vertical one inch and a half edge to it– I have one inch tile that fit nicely there- should I use epoxy for just that vertical edge or thinset? and any tips for keeping the tile in place on the vertical edge would be appreciated- ( polymer additives to the thinset-?-, I’ve seen products like that should I use them??) Any help is appreciated- thanks!

    • Roger

      Hey Monti,

      I would use epoxy for the edge. I would likely use epoxy for the entire table. You have not mentioned what the table is made of – metal or wood, but epoxy would be the way to go for the entire thing. Set the tiles to the top first then epoxy each side piece and use blue painter’s tape to hold them in place until it cures. Polymer additives would bond it initially, but any type of thinset does not get along well with any type of large movement – a table will be subjected to large movements.

  • Michael

    Hey Roger;

    So, being new at this here is yet another question. Laticrete 317 has mixing instructions on their website –

    50 lb bag; 2 gallons LATICRETE 333 Super Flexible Additive or LATICRETE 101 Rapid Latex Admix; 1.7 gallons LATICRETE 3701 Mortar Admix.

    Is this what you do? I was assuming water was all that was required.

    thanks again …

    • Roger

      Hi Michael,

      Those are the mixing instructions to make it a modified thinset. If you just mix it with water you’ll have a very good unmodified thinset – no need for all that fancy crap. :D Should be about 1.75 – 2 gallons of water per 50lb. bag.

  • Michael

    Happy days! Roger …

    I couldn’t get past your proviso that my Ditra warranty would be voided with the Keraflux 2 so I made one last look around. I found Laticrete 317 nearby! Now that is your go to thin set, yes?

    Just out of curiosity, and I know the FlooorElf will know this, why does Schluter not want us to use a modified?

    As always, thanks … (not what does that one captcha want from me? So mashed up!) (and no, I have had no Guinness … yet.)

    • Roger

      Yes, 317 is the good stuff.

      Modified polymers require air to cure fully. Schluter implies that the dovetail shape of the cavities will prevent the polymers in modified thinset from curing properly. I haven’t had a problem with it – but I give my own warranty anyway.

  • Michael

    Hello Roger;

    So I am not able to locate Kerabond at either Lowe’s or Home Depot. They do have a Mapei product called Ultraflex 2/tile mortar with polymer. Any thoughts/experience with this?

    thanks, as always ….

    Michael

    • Roger

      Hey Michael,

      Kerabond is an unmodified mortar – ultraflex 2 is a modified mortar. It is a very, very good modified mortar. I’ve used quite a bit of it.

      • Michael

        ok Roger;

        I found the Kerabond at Menard’s but with a 2 week delivery wait and of course I need it by Sunday (this). So the Menard’s guy (no Floor Elf status I suspect, though) says I can use the Mapei Keraset. It’s only $8 a bag, which makes my uneasy, it’s cheap because it’s cheap …. as in poor quality.

        Any thoughts?

        Michael

        • Michael

          Hey Roger;

          The reason I baulked at the Ultraflex 2 is the instructions that came with the very cool ditra stuff said to use unmodified. But if you have used the Ultraflex 2 (for both floors (with ditra) and walls) then I’m going to go with the Floor Elf.

          … yes?

          The modified basically adds something to help deal with floor movement … yes?

          Michael

          • Roger

            Do not use the kerabond, it’s a very low quality thinset. Modified thinsets contain polymers which retain moisture. The longer moisture is retained in the mix the stronger the cured product will be. You can use ultraflex 2 over your ditra. You’ll void your warranty from schluter but it works just fine.

            • Michael

              … so when you say “do not use the Kerabond” (which you state elsewhere (wow, I swear I’m not a lawyer) is second after Laticrete, I have to say, what?

              … forgive my ignorance, but did you mean Keraset?

              You’re wonderful, by the way … yes, I’ve had a few Guinness. I mean the way you answer all our questions. So cool …

              Michael :dance:

              p.s., why is it that always one of your submit words is usually difficult to discern? Know anything about something like that, hmmm … Mr. FloorElf?

              Michael

              • Roger

                Crap – I did mean Keraset. :D That’s why I don’t use mapei – I can’t keep track of their goofy-ass names. Kerabond is good stuff – keraset is garbage.

                I don’t control the words on the captcha, I do know that I’ve heard from about 100 less nigerian princes since I incorporated it. :D Could have something to do with the Guiness as well, no?

  • John in DC

    Roger, sorry this question isn’t about tile per se, but it is about the subject of setting compounds. In our ongoing Bathroom Project From Hell, we had our guy cut away the bottom 2 feet or so of vertical, wall drywall in the non-tub area (where the toilet and sink are) and replace with Hardieboard (HB). (It was already messed up where the baseboards had been, and there was some mold.) But now it’s uneven, as he didn’t shim it, and the HB is slightly below the level of the drywall above it.

    I need to apply some material to the HB make it level. Do you think I should use joint compound, plaster of Paris, or something else? There will be no tile on top of it–just glossy latex paint and (on the bottom six inches or so) baseboard.

    Thanks!

    • Roger

      Hey John,

      The best option is to remove it and shim it out so it will be flush with the drywall. That may not be an option, though. If not you can use joint compound if it is less than 1/8″ difference or the plaster if over that amount.

      • John in DC

        Thanks, Roger! I’ll see if we can back the screws out and shim behind it. If not, then we’ll slather on some JC. (It’s right at about 1/8 inch.)

  • lawayne

    roger,
    I’m laying porcelain tile in a shower over kerdi, I know to use unmodified thinset under the kerdi, what kind of thinset should i use to lay the tile on the kerdi…..modified or unmodified?…..thanks

    • Roger

      Hey Lawayne,

      You should use unmodified for the tile over the ditra as well. Make sure to use a good unmodified, though.

  • ted

    Hi Roger
    I have a old shower base which is leaking(don’t they all).
    I have replaced the loose and broken floor tiles (on edge of shower Base) and cleaned out all grout and re grouted base. I have put a water proof liquid on this grout two tiles high and two in from walls.

    I have a broken corner wall tile near edge of base, which has been celastic back into its original position. As most leaks would come from these corners my idea was to put a epoxy type resin around this crack as well as around the edge of shower base.

    I was recommended Fixtop 2 part Epoxy thinset.

    Do you think this is feasible or am I like the boy with his finger in the dyke.??

    Regards

    Ted

    • Roger

      Hi Ted,

      I’m afraid the finger in the dyke statement is accurate. What type of ‘waterproof liquid’ are you talking about? If it’s a tile or grout sealer it doesn’t make anything waterproof. There is no product to put over your tile and grout which will make them waterproof. The waterproof aspect of a properly built shower is the substrate itself – it should be waterproofed. If your shower base has a leak the only thing that will stop that leak is replacing the floor.

      While gobs of silicone, epoxy resin or a sealer may slow the process, it will still leak. Short of replacing the floor I’m afraid your effort is akin to slapping on a band-aid after the leg is cut off. It’ll stop some of the flow – but it’s still gonna flow.

      Sorry for the Freddy Kreuger analogy – I’m in a weird mood…

  • Julia

    Yes, it was the same question. I had not realized the first try posted. Thanks for your quick response. What you are saying makes sense. I actually had asked about using the Ditra and this product was suggested. I have not used it because I cannot find much information about it. I think I will go back to the tile store.

    How does the Ditra help in terms of movement? Since it is so thin wouldn’t it move also?

    • Roger

      The fleece bonded on the bottom of the ditra is attached to the plastic, there is flex between the two. The tile does not stick to the ditra – it is locked in there by the dovetail shape of the ditra. It will allow quite a bit of in-plane movement. Read through this to understand how ditra works: Ditra and provaflex

      • Julia

        Thank you. Good explanation of Ditra and provaflex. My island is 6 X 10 so quality prep and work will pay off.

  • Julia

    I am planning to install 12 x12 marble tiles on my kitchen island top. The cabinets and the 3/4″ plywood, when combined with the thin set and tile will be as high as my stove can tolerate. My local tile store advised me to purchase a product “Bondstone Sealer Bonderizer” and said I will not have to use cement board. Would you agree with this?

    • Julia

      When installing 12 x12 marble tile on 3/4″ plywood for a countertop can I use Bondstone Sealer Bonderizer without using cement board?

      • Roger

        Hi Julia,

        Isn’t that the same question? :D

        I have no idea, I have never heard of the product you’re talking about nor can I find anything other than MSDS sheets on it. I have no idea what it may or may not be, nor what it is or isn’t recommended for. I simply cannot find ANY information on it. Do you have a link to the product?

        What I can tell you is that tile over plywood on a countertop is never a good idea. A kitchen sees a LOT of moisture and humidity changes. Wood moves every time it changes. Any material used to bond tile to it must move to compensate – tile will not. This leads to a lot of cracking grout and tile. I do not agree with not using a proper tile substrate over plywood. Be it backerboard or something like ditra, you need to have a proper substrate between the tile and plywood.

        You can use 1/4″ backerboard or ditra, which will raise it a touch less than 1/8″. Does your stove have adjustable feet?

  • Allison

    Hi Roger,
    I do believe I may have gotten myself into a bit of a pickle. i am trying to tile my bathroom floor, can i put backer board over existing tile and if so do i need to thinset and what kind of screws do i use? thank you much

    Allison :lol1: :bonk:

    • Roger

      Hi Allison,

      Um, no. :D

      You can remove the tile and place thinset down and install backerboard over that – but there is really no way to install backer over existing tile which will last long-term.

  • John in DC

    Roger, sorry I’m asking another question so quickly, but I’m quite worried after reading the above. (Wish I’d found this site earlier!) Please help!

    Our contractor used OmniGrip Maxiumum Strength to set the 12X12 marble tile in our bathroom and to set the subway tiles for the tub surround. We had gone into Home Depot looking for thin-set, but he steered me toward this stuff, claiming it was better (as evinced by the higher price).

    Now I’m reading all kinds of warnings against using it for this purpose–that it takes forever to dry and will turn gooey with exposure to water. And yet the instructions on the container say “Suitable for areas with prolonged exposure to wetness, such as shower stalls and tub surrounds.” It does not call itself a mastic, but it doesn’t say “thin-set” either. It contains an acrylic copolymer, which I would have thought would be water-resistant.

    Very grateful for your advice!

    What should I do? Have the guy remove all the tiles (floor and tub surround) and re-set with plain old thin-set? (Thank God we’ve only paid him half so far.) Or

    • John in DC

      I should add one relevant bit of info that may make a difference: Our grout lines (for both the marble floor tile and the ceramic subway till around the bath) are only 1/16. So there is little to crack. I wonder if we wait a week to grout and then use expoxy grout (and seal the criminy out of the tiles), if that will eliminate any chance of water getting under the tiles. Obviously it’s not ideal, but if we can avoid the mess of having everything ripped out, we’ll take it. OK, thanks again.

      • Roger

        John, sealer does not make anything waterproof. It only assists in preventing stains (like cherry kool-aid) from soaking into your grout and stone as quickly – gives you more time to clean it up. Marble is a porous stone – water will get behind it. Your substrate behind the tile needs to be waterproof. Epoxy and sealer will assist greatly in keeping a lot of water out – but water will still get beck there, just not as much.

    • Roger

      Hi John,

      What to do lies entirely with you. All I can do is give you knowledge, my experience and opinions about it.

      The technical data sheet for onmingrip maximum is very vague about this type of installation. It does state that it can be used to install some stone, however, under the limitations it states “Vitreous, semi-vitreous or non-vitreous tile: ceramic” and “Impervious porcelain” as suitable tile types – no stone.

      I believe it is ambiguous on purpose (or purposely ambiguous, if you prefer). While I have no experience with this particular product, and some swear by it as a suitable adhesive for floor tile installation (suitable – not preferred) I do not. While mastics (and make no mistake – that is what this is) have made progress in chemical composition to allow certain tile installations, this specific product, as all others like it, state not to use in submerged areas or shower floors. This indicates to me that it will still re-emulsify, albeit with more moisture or exposure than previous. This is the reason I do not recommend, and in fact advise against, using it for any installation in a shower. It may work with the walls – I don’t know, I don’t use it. I do know that I tear out showers with re-emulsified mastic behind the tile on a consistent basis.

      Also – as ALWAYS – I do not recommend and advise against using any brand or type of mastic with natural stone. Natural stones are porous. The chemical liquids in any mastic can be absorbed by the stone thus permanently transferring through and staining the stone visible through the surface. White marble of any sort is, unfortunately, normally one of the worst. There is no testing number or indication of this issue in either the TDS (technical data sheet) or the MSDS (manufacturers safety data sheet) for this product. The only thing dealing with absorption is the absorption of water into the product itself and it states, and I quote, “<70%". Less than 70%? That, to me, is not a product that should be used anywhere near a shower.

      In short (too late for that, eh?) what he used is a mastic. The manufacturer does not specifically state that it cannot be used for your particular installation - it also does not state that you can. Ambiguous by design, if you ask me. Regardless the manufacturer will warranty the installation provided all installation procedures were followed. That, however, is only for one year. And only for replacement of the material (i.e. they'll give you a brand new bucket of mastic) As to what you should do...? I would sit down with your contractor and have a discussion about your concerns. If he's willing to stand behind his installation, in writing, for an extended period of time and warranty everything (materials, labor, etc.) then you're fine.

      I say that because I do not know the first thing about your contractor nor what type of installations he does or has done. I have, and consistently do, use installation products and materials which some contractors think will never last - but I warranty my stuff for a minimum of ten years. I've had problems - everyone does, it's the nature of construction. If someone tells you they've "never had a problem" they're full of shit. That's a big red flag - you can't control EVERYTHING in construction, things happen. However, I've stood behind every one of those problems and made them right. If your contractor is willing to do that then take his word on it and go with his experience. Basically just make sure your ass is covered. A true professional will have absolutely no problem doing that. He hasn't gone against any specific industry standards or manufacturer's recommendations. Although not my preferred methods he hasn't technically done anything incorrectly.

      • John in DC

        Roger, thanks so much for all your help. Guess we’ll insist the guy rip it out, clean it off, and put it back in using the right stuff.

      • John in DC

        Just to clarify (though I doubt it changes anything), this is not a shower floor, but a bathroom floor, covering all areas outside the bathtub. Also used it to bond the subway tile to the three walls around the bathtub.

        • John in DC

          In case it helps future tile noobs out there: I just tried prying up one of the 12×12 marble tiles; I carefully hammered a metal paint scraper underneath it and pried up. It broke. (It’s impossible to reach far enough under the tile with the scraper to loosen all the mastic underneath.) The tiles are stuck on there pretty tight, and yet the mastic is, after 30 hours, still like slightly-dry cookie dough. Not sure a redo is worth replacing all those tiles, assuming they will all break when pried off, as this one did.

          The marble tiles were from HD and not too pricey ($6/box/5 sq ft.), but the subway tile on the wall was $6/SF from Tile Shop. I’m nervous about trying to pry those off.

          • Roger

            I caught that it was a dry floor and a tub surround. The problem with most mastics in dry areas is with the size of tile and curing time – exactly what you’ve just described. I’m betting the mastic around the edges of the tile was fairly solidly cured, but mastic requires air to cure – something it won’t get much of in the center of a larger 12×12 tile.

            • John in DC

              Roger, thanks again. It was actually sort of uniformly semi-dry, but tearable. Like a Fruit-Roll-Up but less sticky. (Do they still make those?) Or like cold homemade pie dough.

              I think I’m going to have him rip out and replace the marble floor tile but may not do that with the tub surround, given the expense of those tiles and the fact that we have a membrane (a 2mm plastic sheet) behind the tub-surround cementboard–so I believe the worst that can happen with the surround is that those tiles would fall off–vs with the marble floor, water leakage through it could actually reach the joists. (Or should I just bite the bullet and redo it all?)

              The guy didn’t even shim the Hardieboard to the drywall at the top of the tub surround. I don’t think he does this work much. He’s a friend of the family, sort of; he normally does electrical/handyman work for a federal contractor. Honest guy, but no surfeit of planning or common sense.

              • Roger

                Entirely up to you. The shower walls may be fine (as well as your floor), or they may not. I cannot guarantee a failure – I can only recommend and advise on methods guaranteed not to fail. Mastic is rarely a part of the latter.

  • RJ

    I’m in the process of tiling our shower walls. I’ve replaced all the original walls up to 6′ high with hardi but 2′ of drywall remaining up to the ceiling. I’m considering tiling all the way up to the ceiling. Is it necessary to replace the remainder 2′ of drywall with hardi since it doesn’t get wet in that area ? Will I be able to use thinset on the painted drywall?

    Thanks,
    RJ

    • Roger

      Hey RJ,

      No need to replace it up that high and yes, thinset works just fine on painted drywall. If the paint is shiny sand it first so the thinset will bond well.

  • Josh Wales

    I have a question about thinset consistency.

    I tiled the floor and shower walls in my upstairs bathroom, but I’m concerned that I had my thinset too dry. I did my best to measure out the dry thinset and water and follow the directions on the bag exactly, but I had a hard time with my thinset drying out and having to throw it away even though I made pretty small batches (yes, I know I’m slow cause I’m a novice) but more importantly I had a hard time with positioning and leveling the tiles (on the floor or wall), I just couldn’t seem to push them into place, sometimes they didn’t seem to stick well, etc and had to redo them. I got it to work but i’m wondering if my consistency is wrong and it’s making things much harder than they should be. FYI I was using versabond or flex bond from home depot.

    Any way to know if I’ve got the consistency just right? Any recommended technique for measuring out thinset? By weight or by volume? I was hoping there was a class or something I could take where I could see and feel what the right consistency was but I don’t see any in my area (east cost of central florida).

    Thanks,
    Josh

    • Roger

      The consistency should be about like peanut butter (the creamy, not the chunky). It should be workable but should hold a notch well. It shouldn’t be difficult to spread. The directions on the bag do not take into consideration heat, humidity, etc. It’s a generalization. I rarely measure anything so I really don’t know what to tell you the best way to measure it is. The powder by weight and water by volume is how I’ve always done it.

  • Joe

    Roger,
    I just found your site and it sounded very knowledgeable. I done tile before but not in a bathroom and I am about to tile in a shower. We are going to put slate on the walls and ceramic on the floor. After reading some of your comments about the mastic thing for walls it got me thinking because we just bought some premixed NA 2300 adhesive for stone and marble tile and it was a Mapei product that happened to be a Mastic after I researched it. It doesn’t say it on the container though. My question to you is what thinset would be best suited for putting slate on the shower walls (12″ x 12″ tiles ) that are Durarok with Redgard covered? Also what type of thinset for the shower floor, I am put down 2″x2″ tiles on a 12″ x 12″ sheet of ceramic tiles over a mortar shower base.

    Joe

    • Roger

      Hi Joe,

      A good modified thinset will work for both your walls and floor. Since you mentioned mapei – ultraflex II is a good one. Versabond from Home Depot also works well. If you can get Laticrete products the 253 or 254 are very good thinsets. The NA 2300 can not be used over redgard, should not be used on shower walls, and can not be used on the shower floor.

      • Joe

        Roger,

        Thanks, so much for the advice, one more question, what are your thoughts on if I wanted to put an extra layer of Redgard on the shower floor before I lay the tile or will that hurt? When I laid the mortar I put one layer of pre-pitch with Redgard then another layer of mortar to slope towards the drain, would it hurt if I used more Redgard before laying the tile? Or does it need to be directly on the bare mortar?

        Thanks,
        Joe

        • Roger

          Hi Joe,

          Not quite sure how you’ve built your shower floor there. Are you interchanging the words mortar and thinset or deck mud? What is the ‘pre-pitch’? Is that referring to the pre-slope? If so, I’m assuming you have a regular 3-piece shower drain? How thick is the mortar above your layer of redgard? What are you referring to when you say mortar? If deck mud, it sounds like you have a bare layer of deck mud there.

          I’m gonna need some more specific information to be able to answer your question correctly, sorry.

          • Joe

            Roger,

            What I’m referring to is deck mud I guess, I used that Quick-pitch system that has those plastic sticks to help guide you to get the pre-slope towards the drain correct. You pour a layer of deck mud, after it sets you use another set of those stick things to get the final slope towards the drain right but before you put those down you put a layer of Redgard down between the two layers of deck mud as a moisture barrier. So right now I have a bare floor of deck mud, would it hurt if I put another layer of Redgard down or is it not really necessary?

            Joe

            • Roger

              Oh. :D Provided your first layer of redgard was correct the second layer is not needed, and may actually cause problems by trapping moisture.

              • Joe

                Roger,

                Thanks so much for the help, I appreciate all the advice. If I have anymore questions I definitely know where to come, thanks again.

                Joe