In my previous post about thinsets I explained what modified thinsets are and how they came about. That post actually started out as this post, I tend to get sidetracked by beer my dog.
Unmodified thinsets, in one form or another, have been around forever. With the expanded use of modified thinsets, the unmodified version had nearly gone by the wayside with everyone except us hard-headed setters who bought unmodified thinsets and added liquid admixes to them – to create modified thinsets. I no longer do this for my modified thinsets, but it was a hard habit to kick. 
The reemergence (I know – doesn’t even look like a word) of unmodified thinsets came about in November of 2001. At an NTCA / Schluter workshop the statement was made that the preferred method of installation over ditra is the use of an unmodified thinset.
Mass confusion ensued.
This has continued to this day with even seasoned professionals questioning if unmodified should be used, and if so – why and which unmodified to use. This problem is compounded for do-it-yourselfers who don’t have nearly the understanding nor material and product access that we do. It’s difficult to find and purchase. If it helps, it’s sometimes difficult for us as well.
So let’s see if I can shed a little light on the subject and at least let you know which ones to look for and where. This list WILL be a bit biased. If you’ve read anything here you know I’m a Laticrete diehard. It is, and will continue to be, my preferred manufacturer for nearly every tile and stone setting material needed. That said typed, I do realize that other companies exist.
Just like modified thinsets, there are different levels or grades of unmodified thinsets. This is normally measured by the ratio or percentage of cement to sand in the mix. The higher the cement content, the better the thinset. More cement, more sticky, more stable.
It is also, in part, due to the type and percentage of whatever retention product is in the mix. For most thinsets (as far as I can tell – ancient guarded secret and all…) a powder called ‘hydrated lime’ is used. It is the same lime used by brick masons in order to retain water in the cement mix for a longer period of time, thus making the cured product stronger.
So that’s how unmodified thinsets are ‘grouped’ or graded – the ratio of those three items in the mix. Now that you know that, let’s group them in order according to how they are graded and perform. I’ll do this by manufacturer since most people only have one or two specific brands available.
Laticrete 317
Laticrete:
Laticrete 272 is considered the premium (best) – then Laticrete 317. There is negligible difference in these thinsets unless an admix is added to make them modified. For use as an unmodified I prefer the 317. Although they classify the 272 as their ‘premium’, they’re nearly identical.
The difference in these two thinsets: “There is more portland cement in LATICRETE 272 and the sand in the
Laticrete 272
LATICRETE 272 is slightly finer so it is a little bit creamier.” (Thanks to Anita at Laticrete for this clarification) The 272 contains 25-35% portland while the 317 contains 20-30% portland.
On the consumer side Laticrete products often have a different name – you may be familiar with Laticrete MegaBond. That is nearly identical to the 317. I use 317 for almost all of my unmodified thinset needs.
Mapei kerabond
Mapei:
Kerabond: This is considered Mapei’s premium unmodified thinset. It works very well for any Schluter product
Mapei Keraset
Keraset: This is Mapei’s mid-range unmodified. It’s not ideal but it works if it’s the only available. Give it extra time to fully cure! If you use Keraset be sure to wait a FULL 24 hours, at least, before the next step.
Mapei keraflor
Keraflor: The ‘economy’ level unmodified from Mapei. I would not recommend using it for any shower applications or any regularly used flooring surface over ditra. Best to find one of the other two.
Custom Uncoupling Mat Mortar
Custom:
Uncoupling Mat Mortar: This is Custom’s premium unmodified mortar made specifically for Custom’s spiderweb mat and other ditra-like products. It is difficult to find and has limited availability. If you can get your hands on it, use it.
Masterblend: Currently Custom’s only readily available (to my knowledge) unmodified thinset. It is available at most Home Depots. It’s a good sack of powder if you have a flood and need a makeshift levy. That’s it. Any reputable tile contractor will tell you not to use this for anything – ever. I’m one of them. The only really good thing I can say about it – It is an unmodified thinset.*
Custom masterblend
*This is by no means any type of intentional slander or slam against Custom building products! They make some great products. Masterblend, however, is not one of them in my opinion. And that’s all this is – my personal opinion. I do not consider this a viable product with which to install tile or stone over Schluter products.
Tec SturdiSet
Tec:
Sturdi-Set: Tec’s premium unmodified. A good unmodified thinset for nearly anything requiring one.
Tec full set plus
Full-Set Plus: Tec’s other unmodified. Comparable to a mid-range unmodified. It’ll work in a pinch if needed, but ensure full cure time before the next installation stage.
DitraSet
Bostik (Hydroment):
Ditra-Set: This is the best product with which to set anything over kerdi or ditra – it was specifically manufactured for that purpose. The availability is extremely limited, however. Most professionals don’t have ready access to it, let alone regular homeowners. So just plan on not finding this.
If you are lucky enough to find it you’ll feel ecstatic, like the luckiest person alive! If you don’t find it you’ll just think ‘Well, FloorElf told me I wouldn’t find it…’. See – win-win for me. Yay.
So in the groups above it breaks down like this:
Best:
Bostik Ditra-Set
Laticrete 317 (Laticrete MegaBond)
Laticrete 272
Mapei KeraBond
Tec Sturdi-Set
Custom Uncoupling Mat Mortar
Works if limited options exist:
Mapei KeraSet
Tec Full-Set Plus
It’s last call – find something:
Mapei KeraFlor
Go home alone and hold onto your wallet:
Custom Masterblend
So there you have it. The most commonly available unmodified thinsets and where they rate on the scale of quality. As I stated, this list is biased. The list above is the order in which I would use them if given the choice. Regardless of the order under each heading (Best, Works, etc.) this is how they are rated by their respective manufacturers.
Do not be surprised if you cannot find one of the quality products easily. They are not commonly stocked by regular big box stores except for the Laticrete Megabond. The best place to look for any of them would be at a tile supply shop. If, however, you are limited to normal big box stores, you can find some of the common products there.
Lowes will either stock Laticrete or Mapei. Home Depot will only (currently) carry Custom products. Menards normally stocks Mapei. Beyond those three, I have no idea what you may have around you.
You can always check the respective company’s website to find the nearest supplier. Since you will be looking for one of the more uncommon products keep in mind that just because you have a supplier near you does not mean you’ll find that particular product there. It’s always best to call the customer service line and ask them directly where you can buy the product you want.
One last thing – before anyone asks: adding more portland cement to a particular product may or may not make it better. Adding more cement to masterblend, for instance, will not make it comparable to kerabond. It doesn’t work like that. These thinsets, as all tile installation products, are put together in specific ratios in order to accomplish what the company wants. It may work, and it may not work. Unless you personally know someone in the chemistry department of the manufacturing plant there is no accurate way to tell.
ANSI Specifications
All thinsets, as well as any tile installation product, will have a specific ANSI (American National Standards Institute) number on the bag. This determines what type of product it is and what ANSI standard it meets. The number for unmodified thinset is A118.1. The ‘.1’ at the end determines the unmodified version. If you find a thinset you are curious about, and it is not on this list, look for that number. If it has A118.1 AND more numbers after that (with no mention of admix) then it is a MODIFIED thinset.
For instance, if it says on the bag that the product meets ANSI standards A118.1, A118.4 and A188.11 then it is a modified thinset. All modified thinsets meet the criteria set forth for unmodified thinsets as well, that’s why the A118.1 is on there.
ALSO! (I know it’s a pain, I live it) Most bags of UNmodified thinset have the A118.1 number as well as the A118.4, possibly A118.11 also If it does it will plainly state that it only meets the last two standards (for modified) when mixed with the appropriate admix. Masterblend states that it meets all three – with the addition of admix (liquid latex). Don’t let this confuse you. They cannot legally misstate the ANSI numbers.
I hope this helps clear up a little bit of confusion about these products and helps you determine which would be appropriate or best for your project. As always, if you have any questions please don’t hesitate to ask them below. I answer them all. I’m just super cool like that. 
I will check it to see tonight. 10pm will make 48 hours.
Thanks! Yesterday we scraped out some excess that had come up around the glass 1″ tiles. It was very clay like.
Crap..ok…check it again tomorrow…it will make 48 hours. If it is still that way. I imagine I will have to tear it up?
Thanks for getting back so quickly. You Rock!
2 months without a bathroom..
I guess another week won’t matter…ughhhh..
It depends on what’s going on with it. When you check it again see if you can get at some of the thinset in the grout lines and try to scrape it with a hook knife or screwdriver or something and see how stable it is. I don’t see why it wouldn’t be rock-solid at that point.
Hi. I am just laid my bathroom floor, porceline and glass tile using mapei mosaic and glass tile mortar with polymer..after 24 hours, small 1/4″ pieces of the left over morter crushes between my fingers like a cookie into powder. Followed directions exactly for mixing. I hope this stuff gets harder! Is this supposed to be this way? This was a TON of work on a complicated pattern…I am not feeling confident it will hold up…suggestions?
Hey Anthony,
No, it isn’t supposed to be that way. Wait another day or so and check it again.
Roger, i am losing sleep over whether or not to apply a latex modified thin set over 3/4″ TG OSB for the installation of Ditra. Should I use a liquid membrane to cover OSB before applying thin set and Ditra, or am i just being too paranoid about the water in the thin set coming in contact with OSB fiber?
Thanks,
Bill
Hi Bill,
You’re being paranoid. STOP IT!
Install it right to the osb, it’ll be fine.
Hi Bill,
This is a side note regarding what I have discovered about Ditra.
I have personally spent a great deal of time speaking with Schluter directly regarding Ditra installation and they have so many stipulations regarding Ditra and being installed to any subfloor must be with an UNmodified thinset because to properly cure latex modified mortars are required to breath and the Ditra inhibits this. This is according to Schluter.
I tend to be a little old fashioned myself and do prefer to use a latex admix and unmodified thinset or 1to1 because I can control how much latex admix is used depending on the type of installation and the amount of bond strength necessary for the application. The modified thinsets are finally getting the high PSI ratings that we have been using admix to attain so we do use the modified products in certain applications now.
With that, I can and have used the latex (jobsite admix only) modified thinset version over the Ditra with excellent preformance and no failures in the last 10 years. I still will only use an UNmodified thinset to install the Ditra to subfloor for fear of them not standing behind the product warranty.
I know Schluter takes a huge stand that the unmodified thinset for tile installation over Ditra has just as good of results but I want a better bond to stone than what an unmodified product can provide so I do break their guideline in this regard.
I would definately like to hear your opinion on this comment.
Respectfully,
Tim Pounders
President
Pounders Custom Floors
Custom Tile and Stone, Inc.
Las Vegas, Nevada
Sorry Roger,
I was meaning to hear your opinon not Bill as my reply states.
Thanks
Tim
Hi Tim,
Angie is correct, over concrete or a concrete-based substrate a modified thinset is required beneath the ditra. As far as the thinset beneath the tile I’m with you, I’ll use whatever the type of tile dictates. The TCA standards call for modified thinset for most natural stones as well as porcelain. The best we can do is use our experience to decide which of the conflicting standards to follow. While TCA says manufacturers requirements dictate methods, in this case I’m not concerned with schluter’s warranty. I’d rather rely on my real-world experience.
Angie attached the Ditra book and what I see in there is what I read before on page 25.
Tim,
There are two things I don’t get:
1. You are answering both a question no one asked and answering it on a thread and statement that was posted in November, 2012.
2. Everything on page 25 of that booklet has to do with the type of thinset over the top of ditra, not the type below it, which is the subject of this particular thread.
When bonding ditra to cement board or cement they require unmodified, when going over wood it requires modified – hence the ‘depends on the type of substrate’ disclaimer used to cover their ass.
Tim,
Quoting directly from the Schluter Ditra installation manual (http://www.schluter.com/media/DitraHandbookENG-2012.pdf), the thinset between an OSB or plywood subfloor and the Ditra is specced to be “latex portland cement (p.c.) mortar – ANSI A118.11.”
Angie
read page 25 in the manual you attached, it says exactly what I quoted. the type of substrate does not matter they only recommend unmodified thinset above and below.
Can ceramic tile, including porcelain tile, be set on Schluter®-
DITRA with unmodified thin-set mortar?
ANSWER
YES. In fact, we recommend it. Here’s why:
THIN-SET FACTS
Discussion of thin-set mortars and Schluter®-DITRA installations
Portland cement-based unmodified thin-set mortars are dependent on the presence of
moisture for hydration in order to gain strength. Since Schluter®-DITRA is impervious, it
does not deprive the mortar of its moisture. This allows the cement to properly hydrate,
resulting in a strong, dense bond coat. In fact, after the mortar has reached final set
(usually within 24 hours), unmodified thin-set mortars achieve higher strengths when
cured in continually moist conditions.
QUESTION
Can ceramic tile, including porcelain tile, be set on Schluter®-
DITRA with latex-modified thin-set mortar?
ANSWER
We DON’T recommend it. Here’s why:
Latex-modified mortars must air dry for the polymers to coalesce and form a hard film
in order to gain strength. When sandwiched between two impervious materials such
as Schluter®-DITRA and ceramic tile, including porcelain tile, drying takes place very
slowly through the open joints in the tile covering. [According to the TCA Handbook
for Ceramic Tile Installation, this drying period can fluctuate from 14 days to over
60 days, depending on the geographic location, the climatic conditions, and whether
the installation is interior or exterior]. Therefore, extended cure times would be required
before grouting if using modified thin-set mortars between DITRA and ceramic tile,
including porcelain tile. If extended cure times were not observed, the results could be
unpredictable. This is even more important to consider in exterior applications that are
exposed to rain as there is the additional concern of latex leaching.
ADDITIONAL NOTES
15 years of field experience and testing by the Tile Council of North America (TCNA)
support the efficacy of using unmodified thin-set mortars to bond ceramic tile, including
porcelain tile, to Schluter®-DITRA in both interior and exterior applications. See relevant
testing data on page 26.
Remember, the type of mortar used to apply Schluter®-DITRA depends on the type of
substrate. The mortar must bond to the substrate and mechanically anchor the fleece
on the underside of the DITRA. For example, bonding DITRA to wood requires latexmodified
thin-set mortar. When bonding DITRA to particularly dry, porous concrete with
unmodified thin-set mortar, the slab should be moistened to saturate the concrete and
help prevent premature drying of the mortar. Excess or standing surface water must
be removed prior to installation. Additionally, all mortars (modified and unmodified) have
an acceptable temperature range that must be observed during application and curing.
Hi Roger,
I love your site! Now here is my problem. I am thinking about doing my kitchen floor. Half is hardwood nailed over the original sub floor of diagonal 1×6 across the joints that are 16″oc. The other half, done by the previous own, has the original sub-floor, then the hardwood floor…then a 3/4 plywood and then the mortar and tile (who ever did this also didn’t remove the baseboards either, so it looks really good…not). So, my questions are can I put hardibacker or durarock over the original sub floor on the half that has only the hardwood floor? And the other is when I get all that other crap out, I doubt I will be able to save the original sub floor, replace it with 3/4 plywood, then use the hardibacker or durarock so it is the same level all across the entire room? Or tear it all out, and do the whole thing in 3/4 plywood and then use what before I tile, duarock, hardibacker? I have no time frame restraints, I don’t even cook, so being without a kitchen isn’t a problem! Why I am even updating the kitchen is a mystery to even me. My dogs don’t mind the uneven layers and lack of flooring!
Thanks.
Joan
Hi Joan,
Ideally everything would be removed down to the base layer of substrate. Then a 3/4″ layer of plywood over that, then your tile substrate (which can be either durarock or hardi, either one works well, with thinset between it and the plywood). However, if you choose to level half at a time as you’ve described that should work fine as well. Make sure you do have thinset beneath your backerboard, though.
Hey Roger,
I’m ready to install tile in shower in which I used the Schulter Shower Kit. As you mentioned in previous posts you use unmodified thinset for tile installation over Kerdi membrane. I have a glass tile band decal roughly 4″in width in the shower. I was advised by Schulter that i have to use Modified thinset for the glass tile to prevent moisture being trapped.
Can you please give your two cents on this for me. If it is the case, would it be ok to just used Modified thinset for whole shower tile installtion?
Kirk
Hey Kirk,
Yes, I also use modified over kerdi depending on the installation. Just give it an extra day to cure and you’ll be fine.
I am going to my sons to drink beer an redo a bathroom and shower. What my problem is the lower four feet of two walls are concrete. If I fur them out with lumber sucn as treated 2x4s on there side I will loose valuable space in the bathroom and shower. The question is can I put a prouduct called DensShield® Tile Backer by Georia Pacific directly over the concrete wall with concrete screws and a adhesive of some kind, or no adhesive.
Hey Gordon,
Not really a good idea. It’ll create all sorts of differential thermal pockets and lead to condensation behind the backer (your waterproofing – densshield). A better option would be to install backerboard above it flush with the concrete face and use a topical membrane like kerdi or redgard on it.
Hello Roger!
I wish I would have found your site BEFORE starting a tile project, but later is better than never.
Question: what’s your take on putting, (painting), red gard over kerdi band and kerdi st? I have a half bucket of this left over but is it really compatible together?
Thanks,
Dave
Hey Dave,
I wish you would have found me before too!
Redgard can be painted over kerdi. No real reason to, but if it helps you sleep at night it’s fine.
Thanks, I kinda figured it would work but wanted to make sure. Better to use what I have instead of buying a length of kerdi fabric.
Hi Roger. Your site is awesome. I’ve tiled lots (fireplace, showers, counters, floors…), and your site has helped me greatly. This is the first time I’ve used kerdi membrane and I’ve screwed up already. I put it up in the shower over drywall, using keraflor. After two days I could peel if off way too easily. I decided to scrape off the keraflor and start over. I managed to scrape off a couple square feet, but had to wait another day to continue the job. Well now the keraflor is better cured and much harder to get off the drywall. This project is driving me to drink… even more than I do now! Should I cut out the drywall and start over; cut out the drywall and just go back to the moisture barrier and tileboard route; or can I just scrape any ridges and high spots on the keraflor and put another coat of something better over it and then put the kerdi back up? If the latter would work, what thinset do you suggest? I’m not worried about any warranty, so if a modified is best over the keraflor, that’s cool.
Thanks very much.
— Valerie
Hey Valerie,
You can just scrape it down and reinstall kerdi over the keraflor with modified thinset.
Awesome! Thanks. Also thanks for the info about leveling tile depths.
— Valerie
Well crap, I am a resource junky when it comes to doing projects. However, on this one I messed up. The longy short of it, I used custom blend from home depot to install my schluter shower system with tray. I used it on the tray, drain and all the kerdi and seams. I waited the 24 hours and filled with water for some 48 hours. I didn’t have any water drop (except for about 1/16 inch ish). What, if any, issues should I be concerned about.
Thanks for your help,
Brian
Hey Brian,
Sorry for the delay, you got shoved in the spam filter for some reason – you aren’t a Nigerian prince trying to unload your inheritance, are you?
It’s not ideal but as long as it’s bonded well and it passed your flood test you should be fine.
Mr. Elf
Great site; I bought your waterproof shower book as my primary resource for our bathroom tub-to-shower conversion project. Well written and illustrated (your back-peddling notwithstanding), fun reading, remarkably clear, logical & understandable. I am a retired analytical, industrial chemist and I find your insights/explanations unusually accurate/credible (Compliment intended !-)
After studying your monograph, confirming that high quality preparatory work is essential to not only a durable, high quality (“professional’) tiling outcome but also to the ease with which the final tiling can be done (the “fun” part), and then realizing that my wife really wanted this project done yesterday, not after I learned how to do it right, we decided to hire the job out to get it finished (frame-in and board a bench seat, tape and mud joints, pour the pan, set the tiles (wall and floor)). The guy got the framing and floor done and I had to let him go: 1) he called to complain about wall tile not sticking — he was using quick setting quickkrete instead of thinset, a labeled, 50# bucket of which was sitting behind his tile saw!; 2) we are using the divot method and he did a nice job pouring the slope, over both lower and upper drain flanges, without using the Redguard stacked outside the bathroom; and 3) he did not use sand topping mix for the slope, he used concrete mix and there is no evidence (empty product bag, sandy bed texture, etc) of extra sand used. I was able to dig out the upper flange and clean up the lower flange before the cement set too hard, so I figure we can still put down the membrane after the 3 day drying time for the pan. Correct?
And #3 begs my (other) question: I am hoping for comfort, obviously; ‘though good chance I wont like what you have to say, but at least I have to know where we are. How big an issue is the concrete mix use for the pan? Thanks. Keep up the good work sharing.
All the Best
Theo
Hey Theo,
It depends on the amount of deflection in your flooring substrate. If it’s nice and solid then it may be fine, if it is minimal then it is likely to crack. Any cracking is likely to transfer through the tile. The purpose of the sand is to allow the mud deck to compensate for structural movement. Concrete alone will not do that (that’s why they install control joints). If you are over concrete it’s fine. If you are over joists with a minimum 16″ o.c. and a double layer of plywood it’s fine. If it’s a single layer of plywood or your joists are farther apart than 16″ you should replace it with a proper deck mud mix.
Roger,
Thanks for the reply. I was led to believe (by a neighbor who is a floor guy) that I would be OK with the Luan as long as I sealed it and used Ditra over it. So much for that info. I questioned it as well. But as I said removal is not an option since it requires a complete bathroom makeover. :
Decision time. Go with a vinyl again or chance it with tile.
I will follow your recommendations if I go with tile.
Thanks
Great site.Very helpful information. I’m in process of re-doing a bathroom floor. Tore up old vinyl sheet set over Luan. Cleaned the Luan of all old cement. Cannot remove the Luan do to other restraints. I went over the whole floor and added some coated deck screws to ensure the floor was secure. There was a dip in the floor (old house)which required pouring a leveling compound (LevelQuick form HD). I was told that before I did this to brush on LevelQuick Latex primer. Then I poured the LevelQuick cement. It has cured. Half of the floor is still expose Luan.
Questions:
1. Will I need to use more of the Latex primer over the cured cement and also the exposed Luan before using a thinset?One coat is already on the luan, but not on top of the leveling compound.
2. I plan to use Ditra over the luan using an unmodified thinset. Is this correct? Should I set Kerdi-tape on any seams or is it not needed in this case?
3. Can I use the same unmodified thinset to set the tiles?
Thanks for any advice.
Hi Ron,
You’re not gonna like what I have to say – but you likely already know that.
Luan has absolutely no business anywhere near a tile installation. Ever. So no matter what you do to it your installation is not likely to last long-term. I hope I’m wrong. Given that…
1. Yes, use primer over at least the luan before installing thinset.
2. Use modified thinset beneath your ditra – unmodified above it.
3. Same answer as 2.
This is s great site. You are a wealth of information. I am still confused of when to use modified and unmodified thinset for floor and wall tiling tho.
Can you help?
Hey Sandro,
The only time unmodified is required is if you’re using it to install tile over ditra or kerdi, or if you are installing ditra to concrete or SLC. Modified thinset is proper for most any other type of installation.
I have a thought (oooch, that hurt). I may have thought of a legitimate use for Masterblend by Custom. I used it between Hardiebacker and the subfloor. (Of course, I used something different between tiles and Hardibacker.) Don’t you agree that, even though no levies were involved, Masterblend should be up to this task? We’re just looking for proper support under there, right?
Hey Angie,
That is exactly the ONLY thing I ever recommend it for. It works well there.
ACK! Just went to my local Lowe’s used to stock Laticrete products, and in the past month they switched to Mapei! I’m installing Carrara marble 5×18 wall tiles and I have been using Laticrete Megabond with the latex additive. The best my local Lowe’s has is Mapei thinset with polymer additives (yep, that’s what they call it). I’m down to my last 10 sq. ft. of wall tile, should I find a local Laticrete supplier or just use the Mapei (it’s all 5′ above the floor and I already bought a bag, planning to do the last bit tomorrow hopefully.
Thanks for all the great advice. I’ll upload pictures when I’m done, did my niche today, mostly following your very helpful advice (dotting the back tile was a huge help).
Thanks again,
Grant
One other question, you suggested the Tuscan Leveling System to me a few months ago (work has taken priority to finishing the bathroom), and I took this week off to try to finish it. Any trick tools/helpers to getting grout in? I like the epoxy grout, used it for the floor already, but on the wall is there a tool other than a pastry bag to get the grout into the grooves? Seems like if someone came up with the leveling systems someone came up with something to get grout in quickly too.
Just wondering. Thanks again for all the advice and great e-books.
Grant
Why aren’t you using a regular grout float? Use an epoxy grout float and just spread it across the tile to fill the joints.
Hey Grant,
Go ahead and use the mapei, it won’t hurt anything.
Have the grout float, I was hoping there was a reloadable caulking gun or magical wall vaccuum press or something to make grouting walls painless. Oh well, I’ve done it with the float before, I’ll do it again. First try at 2 colors of grout on a wall (Raven then White, following your tips), thanks for all the advice!
On the Mapei, seemed to work fine. It seems as sticky as Megabond, it sets up faster (I actually liked this part since I make small batches) than the Megabond but it’s harder to get mixed smoothly (tends to be lumpy). Also Megabond white is bright white, Mapei white is more an almond.
Have a nice Labor Day weekend!
Grant
GMohr – you can buy reloadable caulking guns at most West Marine boat equipment stores. You want the “#810 Fillable Caulking Tubes.”
West Marine Equipment
Great article here, found it when researching whether Laticrete 317 or Ditraset was better. I’m lucky enough to have the choice of both… Master Wholesale in Seattle WA. No business relationship with them, just info sharing for anyone else in Seattle.
Dan-
Thanks for the info! Great idea! I’ll run over to West Marine and hope my local store carries them.
Thanks again and have a nice long weekend!
Grant
Well, I tried this today, got the tubes at West Marine, mixed up the Laticrete epoxy grout leaving out 10% of the colorant (as the instructions say is OK) to make the mixture more fluid, put it into a big ziplock and filled up the caulking tube and cut an 1/8″ opening…
But it didn’t work. It pushed some of the grout out but when the tube was about 1/2 full it wouldn’t do anything anymore. I cut the tube open and it was solid sand, it was pushing mostly the liquid component out the tube.
So thanks for the idea but I ended up going back to gloves and a grout float and packing the joints and catching the fallout.
Have a good weekend,
G
So, best method is still the
Hi Roger,
I have looked over your website as I have been putting off my bathroom project for the last too many months. I finally put up some of the Keri this past weekend and today saw this post and am starting to panic. I used some stuff from Home Depot made by Custom Building Products. It is not called Masterblend. It is labeled CustomBlend Standard Thin-set Morter. I have only put Kerdi on the floor/curb, one wall and all the Kerdi Band. The one wall was over standard drywall. Do I need to scrap this and and start over? Would I even be able to remove it and start over saving the Kerdi Drain, mud base, and wall?
Thanks,
Greg
Hey Greg,
Customblend is right up there (down there) with the masterblend. It will likely be fine but I would get something else (versabond would be better, even though it is modified) and continue it that. If it would help you sleep better you could remove the kerdi-band and redo the seams with the other thinset. I would not touch the drain. There is enough fleece on the drain that you won’t have a problem with it (nearly a 3 inch overlap if you cut it out with the template). You may not even have to redo the seams, tug on the kerdi-band after about 48 hours and see how well it’s bonded. It may be fine.
Hi Roger,
Will set my drain later today, setting the drain afterwards is going to work out great. Using a brick as a sanding block, how cool was that, used it to clean off any loose remnants.
Bought your kerdi shower and base e-book last week and used it. Read it twice, worth every penny. Verified I was good to build my base, and floated my shower floor out. Thanks to your tips it turned out fabulous, but, I can’t go back into the DMV…. at least for a while.
I found Latricrete 317 (at Daltile for those looking for it in So. Cal.) and I will use it for installing the kerdi. But, and here are my questions, if I don’t care about the kerdi warranty, and if I can afford to let it cure for a month or so…should I consider 253gold instead? what would you do?
I have caulked all of the change of planes with silicone. But what about the joint between the backerboard and the drywall on the same plane? I plan to run my kerdi over this joint and onto the drywall about an inch. Per your book, I don’t have any plans to use joint mesh anywhere in the shower.
Thanks for your time,
Dan
Hi Roger,
Regarding the 253gold, I’m setting 1″ x 1″ marble on the floor and 12″ x 12″ marble on the walls.
Dano
Oh, use the 253 then.
Hey Dan,
If you’re installing natural stone use the 253, if it’s ceramic or porcelain use the 317, it bonds just fine. It works fine with stone as well, I just sleep better at night when I use modified on natural stones.
Just use thinset and kerdi right over that transition, no water is going to get behind it.
People at the DMV have no sense of humor!
Hi Roger,
I installed kerdi in my shower using Laticrete 317, walls first then the floor with a 3″ minimum overlap. After 24 hours I filled Lake Kerdi and let it sit for 21 hours. Immediately upon filling, I noticed two small dark spots form under the kerdi, one about 10 square inches and the other about 36, neither grew any bigger after the first minute or so. I am assuming that water was able to wick between the overlapping kerdi sections. The water level did not drop during the 21 hour test period, I stacked a dime over quarters, see…. I really did read your book!
I can’t see tearing out what otherwise looks like a really good installation. Should I:
1) do nothing
2) apply some kerdi seal (?) (the chauking stuff) over the joint
3) install kerdi band over the joint
4) go put my dog out and/or take up drinking
Once again, Thank you So Much,
Dan
Hey Dan,
I would probably install a layer of kerdi-band over those seams just to be safe. Easier to do it now if there isn’t a problem then actually having a problem due to this later. It’ll probably be fine, but why take the chance when you don’t have to?
Then take up drinking.
Roger, I have a quick question or two or maybe three. Who’s keeping count? I am going to be doing my first tile install soon and want to avoid some of the issues I have read about in other forums like thinset failure to bond to tile…etc. I know Laticrete says the 272 is premium meaning their best I guess. But you list it slightly below the 317 which is your preference. What about 317 makes it better to you? Second, what tips would you give when making the batches? For example best way to mix…etc. I read where some have said the megabond did not grip tiles after 24 hours when they used it on install. I am sure it was the installer’s fault but Should I wait more than 24 hours for unmodified to set between each step to ensure it bonds properly? When I install the Ditra, should I use a damp sponge to moisten the backerboard before the unmodified? Thanks for your time and the abundance of info you give to DIY wannabees like me.
Hey Joseph,
I prefer the way the 317 feels as I work with it. It seems creamier to me. It’s simply a personal preference, either will work just fine. Pay attention to the working time and only mix up as much thinset as you can use during that time. I use a big ass DeWalt drill with a mixer bar that looks like a cake mixer. 24 hours is plenty of time to wait, they apparently did not get full contact. Yes, moisten the backer before installing the ditra.
Roger,
My local Lowes doesn’t stock laticrete any longer and the only unmodified Maepi thinset they have is labeled as “Floor and wall tile mortar”. They acted like they had never heard of kerabond! Will this product produce reliable results over ditra?
Hey Greg,
The floor and wall mortar is fairly comparable to the keraflor. It’s a bit better, though. It’ll work fine.
Well there you have it. Heading back to Home Depot now to return my big bag of crap…
I think I just blew up the dog, just had my family room floor taken out of 20 plus years. It looked pretty good for porecline tile. It had durock 1/2″ straight on top of cross layed 3/4″ by 6″ planks with 1″ gap inbetween on wooden joists spaced I don’t remember. The floor was solid, I could jump on it with a pogo stick. My whole family and friends including my 300 lb. brother in law could excercise to the WII fit and did, we never had anything break or crack on the floor. Well had it replaced with hariboard 1/4″ with a little bit of thinset then concrete mix, then a little bit of thinset on back of this beautiful thicker travertine tile (french patern) with this thin bone colored grout that was perfect. Well the next day after I paid the installer and started sweeping up the dust to put on my $125.00 dollars worth of stone enhancer, I noticed that the grout lines were turning to dust in the middle of the room. I think I’m in big doodo. What can I do without ripping this out and spending alot more money. Can I just take the grout out and forget about it? Can I pour gorrilla glue over everything? He says he is coming back to pick up his garbage on Friday and will regrout for me. From what I’ve read here, I think this won’t help. Can I go under the floor and buttress up the joists in the middle of my floor with concrete blocks and 2 by 4rs? How about adding another joist or two next to the ones I have already down there. When I stomp on the floor (lightly) the grout bounces up. The floor always vibrated a little when you stomped on it. I just does it more now. What is the least expensive (least time consuming way to fix this)? My wife goes back to work as a teacher in two weeks. I already took 3 weeks off to oversee construction work at house. It didn’t do me any good. Kindly advise. Man with no dog.
Hey Urbano,
I’m a bit confused about the ‘little bit of thinset then concrete mix’? What is the concrete mix, and why is it there? If your cracking grout is due to movement then anything you can do to shore up the joists will help – a lot. Cutting the span of the joists in half will strengthen the floor tremendously, especially if most of the grout problem is in the middle of the floor.
I have to tell you – I just had a very shitty day and your first sentence literally made me bust out laughing. Thanks for that!
So here’s the conundrum I’m in. In the next week or two I’m about to take on the task of breaking out my old cast iron tub, tile and concrete board(mixed with chicken wire?) and replace it all. The major problem I have in front of me(besides this will be my first shower tile job
) I have one bathroom in my house and no RV to ack as a second shower/depositing throne for my wife to use. Me, I got the backyard and showering is over rated. The way I look at it is I got three days to remove and replace all said items. I just bought some of that Masterblend from home de-pot but will return it and go to so-lowes and get some Laticrete instead. It’s taken some rambling, but here’s my question. I have you had any experience with Laticrete Multipurpose Rapid Thinset? It says it allows grouting in 2 to 4 hours. With the time I got to do this job, any corners I can curve to save time would be saaweeet 
! Any ideas for me? I’m a DIYer with not a lot under my belt besides some cahones to give it a try. Please give me some ideas, criticism or something to go on.
Thanks!
Bane
fyi, that’s my real name. I’m not a huge batman fan, lol. Although they are some great flicks.
Hey Bane,
The multipurpose RS is a good thinset. The best advice I can give you is to mix up very small batches until you get used to it and follow the set times on the bag. Once it fires off (begins to cure) you’re done with it. Don’t get too crazy with your batch sizes.
Other than that it is good stuff and you can grout in that time frame.
Crap, I wish I had read this a couple of weeks ago. I just finished tiling a shower with granite over Kerdi using Keraset. It’s all my local Menards had. Is my dog going to burst into flames from using this? On a related note, I’m about to do 13×13 porcelin tiles over Ditra, will Keraset work or should I hunt down something else.
Thanks
Chris
Hi Chris,
I think your dog is safe.:D Keraset will work, just give it an extra day to cure before grouting. Not to enable it to cure – it’ll do that anyway, but to get a good grab with the initial cure before you start to jostle the tile around.
Hey do you let aussies on your website or shoot us on sight for straying from our paddock? The language barrier is tricky, I think what you call thinset we call “tile adhesive” and of course we lay a square metre not 10 square feet.
Now over the years Ive laid two bathrooms and a kitchen with out any grief so naturally that makes me an expert!!! but just in case your 20 years of experience gives you a slight edge I wanna ask a couple of things .
I am laying two rooms ( joined by one doorway ) which are both too small to need a soft joint but if you measure the longest distance across both rooms through the doorway its over the 5 metre max.
Ya reckon I should put a joint in the doorway or just do the experiment and see if any thing pops up?
Also , whats your thoughts on the new spacers that help keep the tiles level as they set? are they just for wimps ? My thought was that they coudl cause trouble if they hold one tile up higher than the adhesive ( thinset) would allow and hence leave an air gap. Im gonna try use your method and also the clips so they tiles dont move when Im not looking.
thanks for your time and if your answers make sense I’ll tell you the secret of which aussie beers are the best (tip: its nor fosters, we dont drink that here which is why they send it overseas)
cheers
Sam
Hey Sam,
Of course Aussies are allowed – it’s those damn kiwis we try to keep out!
I would likely install a soft joint in that doorway. It’s actually the ideal spot. If you watch people walk through a doorway (yes, I’m easily amused…) you’ll notice they never, or rarely, ever step in the center of the doorway. It’s likely they’ll never even walk on that soft joint.
There are several leveling systems out there. The two I’ve used are LASH from Qep – it wears your fingers out quickly and you need a LOT of tile adhesive beneath the tile for full contact. I have used, and still use, the TLS. It’s expensive but the results are worth it. When I had a beer with Mick (the inventor of TLS) (and yes, I know people
) he claimed that the system does not lift the lower tile up to meet the higher, which would leave a void as you’ve described, but rather pushes the higher tile down to meet the lower. It sounded like marketing BS to me but thought I’d give it a shot just to see. He was absolutely correct. The TLS system pushes the higher tile down to meet the lower, resulting in more coverage rather than less. The LASH? It does the opposite – it can leave voids.
I don’t drink that fosters pisswater either.
I prefer a Red Hill Imperial Stout or an Epic Portamarillo (sp?) when I do partake in an upside down brew. Always open to recommendations, though. 