Thinset explained

I am often asked what type of thinset should be used modified or unmodified? So to answer this question you first need to know what kind of tile is being installed and on what kind of surface. Let"s understand how thinset works and how it bonds to the tile and to the substrate it is being applied to. Thinset is basically a mixture of sand, and cement and other compounds to facilitate the hydration process. Thinset is the “Glue” that bonds the tile to the surface to which it is applied, and it does this by growing crystals as it dries and cures. The crystals interlock and penetrate into the surface of the tile and the substrate, bonding it all together. The longer the thinset is able to grow crystals the strong the bond and the strength of the thinset. So what kind of thinset should be used in any given application? Well there is unmodified thinset, and modified thinset, and other kinds of thinsets, but we are just going to deal with these two types which are the most widely used. Unmodified thinset is a thinset that has no polymers added to it, a modified thinset is a thinset that has either polymers added to the powder during manufacturing, or an unmodified thinset that is mixed with a liquid polymer on the job site just before it is to be used. Modified thinset is the most widely used mortar these days and is recommended for most applications and types of tile. So why is there polymer in the thinset anyway? Well it is there to help the thinset retain moisture so it can grow those crystals we talked about earlier. Many of the substrates that tile is installed on are very porous and thirsty and will absorb the moisture present in the thinset, which in turn will prevent the thinset from gaining strength, the polymers help with this problem by keeping the moisture in the thinset so it can Hydrate (grow crystals) properly. So when you go to the store you will see that not all thinsets cost the same, some are more expensive than the others, well you get what you pay for, the cheaper thinsets have less of the needed components, and the more expensive ones have more, so by extension better. Modified thinsets also add an adhesive quality to the bonding mechanism, as well as flexibility, enhancing the strength of the tile assembly. So modified thinset is used to install porcelain tiles on all kinds of substrates that call for a modified thinset, but we are not going into that here, because I am just trying to explain how thinset works, not specific applications, except for one.Now unmodified thinset was becoming a seldom used product until Schluter came along and required it for installing tile to Kerdi and Ditra. Now unmodified thinset, as the name suggest, has no polymers. So what is the difference and why should it be used on Schluter products? Here is the thing, the polymers in a modified thinset help it retain moisture, but if the tile does not absorb any moisture, and the substrate is also impervious, then the moisture in the thinset becomes trapped, because of the polymers it need to evaporate for the thinset to dry completely, extending the drying time greatly. The only place for the water in the thinset to escape is the grout lines at the edges of the tiles. So this is where unmodified thinset has an advantage, trapped moisture in this case becomes a benefit. In unmodified thinset moisture that is not consumed by the hydration process will not impede the hardening of the thinset and will eventually escape. The damp cure that the impervious sandwich creates only makes the thinset stronger and promotes a very tenacious bond to the tile. So that’s how thinset works and I hope this gave a bit of help to decide whether you need an unmodified or modified thinset for your install. All tile installed by Sal DiBlasi, Elite-tile Company, in the Boston North Shore area. This video contains affiliate links, which means I will receive a small commission if you click on the product link.
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[@jerrysmith9780]

Sal, I've been around tile setters for many years but I've never heard it explained in such a basic format. Thank you for this valuable information. I always wondered if it was a Schluter "sell job" of telling us we needed to use unmodified thinset on Kerdi. Also, as a Professional Engineer. it's helpful when you repeat key points. It reinforces the point to us as listeners and subscribers. Don't be discouraged by the fella in that post below that thought repeating ideas is unnecessary. It is actually very helpful when we are watching your videos to learn. Ciao!

[@pedrhipo]

Great explanation, very specific. Thank you.

[@karaandrichbrophy2368]

Sal, LOVE your videos. Thank you for taking the time to enlighten so many of us. I had hardibacker installed before I decided to purchase kerdi membrane. Will the kerabond T I have make a good bond between the hardibacker and kerdi? And if I am using 3x6 tiles, what thinset would you recommend (I know Kerabond T is meant for large format tiles)? Thanks

[@SalDiBlasi]

Hardibacker will work, but it is really thirsty, make sure you sponge it down really well before you spread your thinset or the hardi will suck the moisture right out of it. Any good quality unmodified thinset will work. if you read the label on the bag of the thinset it should tell you how to mix it so it performs like regular thinset.

[@karaandrichbrophy2368]

Thank you so much. I have another question on this job. When the hardibacker was installed, they used drywall mud where the hardibacker meets the drywall on each side of the shower. It extends into the shower where I want the kerdi to be. Do I need to prime everywhere the mud is? If so, does it matter if it is oil or latex based?

[@jofprexus]

If tile laid on a porous surface needs modified, what should be used on a surface treated with RedGuard (or equivalent)?

[@SalDiBlasi]

Liquid applied membranes usually call for Modified thinset.

[@donbankstontileman]

Great name for a product Sal....It's thin and you set tile over it...LOL...You are doing a great service,by teaching people who want to learn about tile installation,and want to install it the right way,with the right materials...Your video's are excellent!..

[@DonnaShanks]

I am stunned. I have looked at so many videos. I've done enough Google research to write a dissertation but NO ONE and I mean NO ONE has explained this as clearly as you. Bless you for taking the time to do such a clear and excellent video. Thank you to your filming and editing team as well.

[@SalDiBlasi]

Glad it was helpful!

[@coldhardysucculentswithkdw4988]

As an old time Plasterer I thought this was a very informed video. Plasterers don't often use thin-set, but we do understand polymers so thanks for this. well made.

[@460sw3]

thank you for taking the time to make these videos. every time I watch, I learn something new. my wife and I are starting our remodel of the kitchen (400 square feet) and we are diy people but have never messed with tile, but feel confident every time we watch and learn something from you.

[@588158]

Excellent! You are one of the very few Tile guys on KZbin who really knows what he is doing and knows the technical detail of how and why its done.

[@Plumpplumberbalding]

Great! I've learned a lot from you. I've started installing tile as well as general Plumbing repairs. Thanks for your videos.👍🎓🎯

[@DXWXMX44]

Thanks for the explanation - I called Schluter about the modified/non modified question on our last shower. They said to use "Schluter Set" but not why. We did - no problem. I hadn't heard about "growing interlocking crystals" until this video.

[@chrise202]

If moisture cannot escape, but needs to - Use unmodified If moisture can naturally escape - Use either, but modified would be better bond. Got it.

[@craiglair1080]

Very informative video Sal. Thank you for the advice.

[@ElMareevanZweel]

Most useful explanation I have come across, thank you!

[@hew8you]

Which unmodified thin set do you recommend for Schluter? The All-set is not available in my area…

[@Dezdamoonbear]

What about laying tile over tile? I've seen it done before. What kind of thinset should be used in this process and how long do you think this process will last?

[@lrbsomethin3720]

can you make a video of reccommended tools on a budget. im a buyer of good quality tools but maybe somethings i can save on. thanks for the videos.

[@joshjosh575]

Is there a English version of this video?

[@ecospider5]

Fantastic description thank you.

[@kristinekoski7345]

"YOU ARE DEFINATLY A MAN , OF MANY WORDS! But that's good,. Becuz you taught me a whole bunch, and you sound like you do know what your talking bout,. SO CHEERS TO SAL! "SAL AND HIS SALOUTIONS"!

[@SalDiBlasi]

😊👍

[@mikefuson176]

Very informative. Thanks

[@brentcooper231]

we are just starting on a bath remodel with Schluter and this video clears up a lot... Thanks!

[@SalDiBlasi]

Great, glad it helped.

[@bluekeet]

Hello sir, if i use waterproof membrane on backerboard, which type of thinset should i use for porcelain tile?

[@SalDiBlasi]

+bluekeet Modified

[@davida3343]

What’s the difference between white thinset vs gray thinset?

[@SalDiBlasi]

Ther color. You need white for glass tile, natural stone tiles and some other types, otherwise they are the same.

[@jakes1344]

Like to set my schluter pan and let it set a day can I use speed set so I don't have to wait that extra day

[@SalDiBlasi]

+Jacob Sewell What exactly do you mean by "Pan" the membrane, the tray or the entire thing. Schluter recommends unmodified thinset.

[@jennifercrow794]

so making thinset a little on the wetter side and letting it sit longer will create a stronger bond?

[@SalDiBlasi]

No, that is not accurate.

[@crossbalsamo8485]

I wanted to ask. I'm laying ceramic tile in my shower. I used the rubber pan liner and waterproof membrane. Do I have to apply sealer when completed?

[@cz3chmonkey]

+Cross Balsamo grout sealer? of course

[@SalDiBlasi]

+cz3chmonkey Better to use a stain resistant grout, some of which explicitly say not to use a sealer.

[@rjakethomas]

I had that concept in my head but you made it clearer. Thank you! I was looking into it because I was curious about using my extra modified then set to screed it into ditra. If I'm not setting tile that day. By this logic it should be just fine to do that and then come back and set tile with an unmodified on top of that

[@BonBon770]

Key in substrate

[@ceeIoc]

can I use Schluter All Set for glass tiles in a shower?

[@SalDiBlasi]

No

[@wallacegrommet9343]

Plus, the polymer additives cannot gain stre if they can not dry completely within a short time frame. Who wants to wait six weeks to use a shower?

[@charisma-hornum-fries]

So when using a tile with little absorption and only has the edges to evaporate from, would it be best to just wait a day or two more until grouting the spaces? I imagine that bacteria and other dirt would be lesser able to settle under the grout if it’s cured before grouting??? I love your channel and have learned so incredibly much from you. I am so very grateful and humble to learn from such a craftsman as yourself.

[@sean9462]

Thanks Sal, any public speaking class will teach you that you repeat your idea a minimum of 3 times to ensure the audience gets the message. Thanks for all your hard work and I appreciate your years of experience and knowledge.

[@bluesriot2]

Hey Sal the homeowner used 'goof-off' to remove the paper backing of the old linoleum that was left on after the linoleum was pulled up - there's half inch plywood over the old subfloor for the substrate - will the goof-off prevent the tile from adhering ? thanx -great video

[@kingarchnyc]

Looks like new cabinet installation, so not why sure he would tile around the cabinet instead of new tile underneath entire floor... the money you saved is not worth it.

[@mikunan]

Sal, Thanks for the great informative video. I really appreciate you answering so many of the viewers questions, which is helpful to all.

[@zlinko2339]

Thanks for video. I've been looking everywhere for this information !

[@ikust007]

What a marvelous/scientific explanation . Love it: Artisan & Science.

[@pingpong9656]

Do you have a video on how to demo/remove a ditra tile installation on plywood and concrete floors?

[@jlai3861]

But then Schlueter came up their own modified thinset called allset they claimed it can be used on any situation. Why?

[@SalDiBlasi]

This video was done before AllSet was available. The reason that modified thinset can be used is because of an advancement in thinset technology that has made it possible to have a chemical dry of the thinset between two impervious surfaces. Many of the newer modified thinset from other manufacturers can be used for this type of installation.

[@jlai3861]

@@SalDiBlasi Thanks, I was hesitate to use modified thinset between membrane, I will give Allset a try.

[@quedogkualum]

Should I use modified or unmodified thinset on durock using porcelain tile?

[@eugencristea1585]

Both types of mortars (white or grey) can go under any Schluter products and under any type of tiles installed over Schluter products with two exceptions. Both types of mortars cannot be applied over vinyl material and also the un-modified one (grey color) cannot be applied over plywood or OSM (particle boards). If you install Schluter products over plywood or OSB subfloor, don't use the grey one (un-modified - Schluter Set), use the white one as it sticks and has a better bond. I did complete the four days course from Schluter and I have to admit we used in class for hands-on training, the grey one, un-modified. I guess because is almost half price cheaper than the modified one and with the same result. Here is the link for Schulter thin-set for more details: www.schluter.com/schluter-us/en_US/select-thin-set

[@SalDiBlasi]

The suitability of a mortar for a substrate or tile is not the color, that is irrelevant, what counts is the standard it conforms to. watch this kzbin.info/www/bejne/eHvSgXt9qdqep9E

[@TaeKenDo]

Hi, I'm in Canada and I do repairs for a restaurant and they needed me to replace 1/2" x 6" x 6"tiles in the service area which is where the most daily traffic is and where they move their heavy grills, tables & fridges to clean behind them every night. I went in at 8pm on dec 24th, we were closed on the 25th & only opened at 8am on the 26th. I took up the broken tiles, cleaned the surface down to the old self-leveling cement and used modified thinset around 1am to apply the tiles and then did the grouting between 2:30 & 4:30 am on the 25th starting with the tiles first laid.. This would give more than 24 hours drying/setting time but employees came in on the 26th and as usual and disregarding instructions to not move the (several hundred pound) equipment onto the freshly laid tiles, they did so and dislodged & cracked several so the job needs to be redone. In a restaurant as you know, health/cleanliness is always an issue so they need to clean every night behind these heavy machines and to do so must move/roll them onto the freshly tiled area, so do you have any advice on what easily available product(s) to use and also any tricks to avoid this repeating itself...? Price shouldn't be a problem. I suggested laying 3/4" plywood over the traffic area and screwing it down for a week to let everything properly set but now I'm told it cannot stay on the floor for 1 week, I suppose because they would need to move the machines to clean behind them. Also the last employee typically leaves at 3am but the first one in is at 7:30 am that same morning...not a big window to get the work done. If you have any advice on how to get around these obstacles it would be very much appreciated. I was using regular thinset mortar and Mapei Polymer Sanded Grout. Thanks in advance!

[@SalDiBlasi]

They want it fixed, but wont give you the needed time to have the materials cure and set, seems to me that they are asking for the impossible. That being said, I would look for a very fast setting thinset and use that. www.ardexamericas.com/en-us/Documents/TechData_En_X7R.pdf

[@TaeKenDo]

It's kind of a catch 22, tiles need time to cure, they need to do their jobs & both interfere with the other. Thanks for the link.

[@leopalmeri8449]

do you recommend 3/8" trowel or 1/2" trowel to use for a 12x24 tile?

[@SalDiBlasi]

1/2"

[@Unregistered007]

Thanks Sal ! :)

[@renato_guitar2138]

Sal DiBlasi great job.. are you from Italy? Thanks!!!

[@craigstevenson464]

What is the difference between Unmodified and Fortified Thinset if any?

[@rickroll9086]

Thanks Sal. I notice you use modified Mapei over AquaDefense (as recommended). AD is also impervious to moisture (like Schluter), so why does modified work between two impervious surfaces for Mapei but not Schluter? Similarly, Schluter says use unmodified between cement (porous) and Ditra. I’m sure you also know that unmodified has to be super sloppy/wet for Kerdi and Ditra to bond to the substrate. I still don’t quite get why can’t use modified for Schluter!

[@SalDiBlasi]

With some advancements that have occured over the past few years, that is not as much the case as it used to be.

[@gregsteinke5421]

Huge help thank you

[@SalDiBlasi]

Thanks, glad it helped

[@588158]

Sal, I would like to know your view on the durability of a tile (porcelain & ceramic)installation using the practice of each the following methods as opposed to laying tile on a dry and set deck mud base.1. immediately laying floor tile using thinset after putting down the deck mud base (while it is still wet).2. Sprinkling Portland cement over still wet deck mud base and laying the tile on the Portland cement . thank you.

[@SalDiBlasi]

Portland cement is not a good idea, not designed for tile adhession, however using thinset and back buttering each tile an set into fresh mud, or a loose mix of thinset on the mud can work. I have seen the method you describe fail many times. Depending on the type of tile Portland cement may work, but a dense vitreous porcelain tile has very little chance of success in my opinion.

[@NaturalScotti]

Ardex says their X77 microtec modified thinset can be used on uncoupling membranes. Have you hear this Sal? Do you agree?

[@SalDiBlasi]

Yes it can, no problem

[@NaturalScotti]

@@SalDiBlasi thanks for the quick reply. can you explain why it's ok to use this modified thinset between the ditra and tile when schluter asks for unmodified?

[@SalDiBlasi]

Actually it has been a few years now that advancements in mortar technology has seen the development of many new mortars that make it possible to use a modified mortar between two impervious surfaces. These mortars will cure and harden without the extended dry times, they no longer need evaporation of excess water to harden and dry. Schluter makes its own mortar, "AllSet" which is a high polymer content thinset Mortar that meets ANSI A118.15 specification, which they recommend to use for the installation of all Schluter products and also to set tile over those products. Also many manufactures will substitute their warranty for that of Schluter, if you use one of their approved mortars to set tile on Schluter products. The issue has never been whether a polymer modified mortar would work on Schluter uncoupling membranes or waterproofing membranes, it has always been about the extended dry times needed if they were used, that is why they recommended the use of an Unmodified mortar that cures and dries by Hydration. As a side note, the manufacturers of all other membranes never required the use of an unmodified mortar.

[@IainMiddleton]

Again !!! A brilliant educational skill set.

[@absolutemalmaute9592]

If I’m installing Schluter Ditra to my cement basement floor, which mortar do I use? I’m new to tiling but would love to do our basement that’s $800sq ft. Any cheaper mortar you recommend besides the Schluter brand to install the Ditra on the cement?

[@SalDiBlasi]

Pretty much any good quality mortar will work to install the ditra on concrete, unmodified or modified.

[@absolutemalmaute9592]

Will there still be a warranty with Ditra if I use a different mortar brand though?

[@SalDiBlasi]

@@absolutemalmaute9592 Yes as long as you use an unmodified to set your tile on the ditra.

[@KG-sk8qc]

So over regular concrete modified thin set good?

[@SalDiBlasi]

Yes, absolutely

[@KG-sk8qc]

Thanks Sal!

[@johnharvey4496]

Ask not what you can do for your tile job... Is this the accent from the American northeast? - he sounds a bit like (former) President Kennedy? Rob Melbourne... Australia

[@SalDiBlasi]

Boston, Massachusetts. Yes same are as JFK.

[@JohnDoe-du1no]

Modified thinset bonding agents in it unmodified no bonding agent

[@dalehayton4007]

Hm. Don't U guys use dust primer

[@modsavant]

After watching dozens of tile installation videos by a dozen different people, I have concluded that you, Sal, are the smartest one of them all. Thank you for explaining it scientifically so that I can use different thinsets correctly.

[@SalDiBlasi]

Thanks 👍

[@dancegirlhaver3182]

Wow thank you for your valuable info! I'm doing my bath redo myself, and was searching for info through many videos.. Everything you said gave me the final clarification to all the knowledge i had previously attained. Thank you! Very much!

[@SalDiBlasi]

You're welcome.😊

[@Ifugiveubegin2live]

What kind to use when attaching granite to sealed concrete outside ( a pool spa spillover) is what it is. Thanks. Go.sox

[@markk4015]

Sal, great videos by the way. When asked, you said you use TEC Uncoupling Membrane Mortar on Kerdi board. The bag doesn't say it's unmodified. In fact it says there are latex additives in it which would make me think it is modified. For that application Schluter calls for an unmodified thinset. You don't seem to be a fan of Laticrete 317. TEC is hard to find. Any other recommendations for thinset using kerdi board/band?

[@SalDiBlasi]

TEC Uncoupling Membrane Mortar is an unmodified mortar www.tecspecialty.com/products/mortars-and-mortar-additives/dry-set-mortars/Uncoupling-Membrane-Mortar.html#.WN7PZzvyuUk If you can't find that Try Mapei Kerabond, or Bostick Ditraset, 317 will work, but it is a lower grade Unmodified Thinset. Schluter has just come out with its' own thinset, might be hard to find for now.

[@propaycheque]

I use Megalite for everything and its held up really well under and above ditra and with heating cables under and above the ditra (pre ditra heat). Youre the man, Sal, what do you think? Is there no such thing as all-purpose premium or is the 1.86 CAD per sqft just too much money?

[@SalDiBlasi]

+Pro Paycheque If you want to maintain manufacturers warranty, Ditra calls for unmodified on top and the appropriate kind under depending on what you are going over. If you don't care about the warranty then use what ever works for you. 1.86 seems excessive

[@joshuagraupman1634]

Why can modified be used on other water proofing systems, but not schluter? I have seen videos where guys find the thinset still wet under tile. Should I use modified for setting my large format wall tiles with water proofing under it?

[@SalDiBlasi]

Schluter requires unmodified to set the tile, unless you use Schluter Allset thinset. kzbin.info/www/bejne/bX-VnGSIo9KYgKs

[@lousilva5041]

Sal, I'm currently addressing an issue with my upstairs bathroom. While in the process of repairing the mess a flange leak caused, I've encountered a few of your video which helped me tremendously. Thank you so very much for sharing your collective knowledge!!

[@SalDiBlasi]

That is why they are there, to help people that come across them.

[@rezakarami2179]

How can you tell if the tile will absorb moisture or not?

[@leopalmeri8449]

when using 12×24 tile for a bathroom shower, also using Densheild backer board do you recommend unmodified or modified thinset . and how do you lay out a 12x24 tile pattern vertical or horizontal Wood plank on the walls?

[@SalDiBlasi]

Use modified, layout is different for every bathroom.

[@mikebabcock8528]

Hey Sal, I see you use mapei ultraflex 2 which I use often for tile over plywood. What glue do you personally use on kerdi board? I've used kerabond on kerdi membrane before, but found it hard to use on walls. The mortar you used seemed to stay on the walls better. Thanks in advance, your videos are awesome!!

[@SalDiBlasi]

Most of the time I use Tec Uncoupling membrane mortar

[@truegrit7697]

Great help! Thanks for sharing.

[@jhurley516]

I bought the red gard uncoupling membrane.. it says only use modified thinset.. is there a difference between ditra and red gard?

[@SalDiBlasi]

yes use whatever the manufacturer recommend, red gaurd is a liquid applied membrane, very different to Schluter

[@chrisrobinson5413]

Thanks for sharing sal. You are awesome

[@streetsloveus6820]

Smoke a joint sit back and listen to this man !!!!! Great video!

[@keithstanton4504]

Wow,that is exactly what I am doing but with a glass of wine with it.Nice!!!

[@RayGregoryiam]

Sal, what a great video and explanation, It seems in this case the only time I would want to use unmodified is over Kerdi, would I also use unmodified when setting tile on denshield as it also seems to have the same moisture properties.

[@SalDiBlasi]

+Ray Gregory Schluter requires the use of unmodified thinset over Ditra and Kerdi, Denshield is another animal entirely and modified should be used.

[@brotherjoeradosti]

Sal, do you like Laticrete 317? and have you used the new Schluter Thinsets yet?

[@SalDiBlasi]

I have used 317, but I find it is on the lower end of unmodified thinsets, I intend to use the new Schluter thinset, not yet available, but will be very soon.

[@cannarris]

How come the manufacturer of redgard recommends a modified thin set for their product? If the tile and substrate is moisture proof why not non modified?

[@SalDiBlasi]

Schluter is the only manufacturer that calls for unmodified.

[@ExperimentLife]

it looks delicious! like ice cream!

[@CDMANNING11]

thanks for your time makes sence

[@nickroberts4586]

soooooooo, play it safe and just always buy modified if you dont know which to use

[@SalDiBlasi]

Actually not the case.

[@brandonbooth30]

Hi Sal how long to wait for the modified thin set to dry if using an epoxy grout ?

[@SalDiBlasi]

Read the direction on the type of mortar you are using, but usually 24 to 48 hours, some are 12 hours.

[@asinger261]

What exact brand of unmodified thinset do you use for LFT over kerdi?

[@SalDiBlasi]

Tec, uncoupling membrane mortar, or Bostik Ditraset, or Schluter Set

[@DiannaAtherton]

Wow what a great video. Getting ready to lay down 12" porcelain tile on durock kitchen countertops and a 8" tile backsplash. Which thinset do you recommend? Thank you Sir!

[@SalDiBlasi]

Use a good quality Modified thinset.

[@DiannaAtherton]

@@SalDiBlasi sal, can I thinset my tile backsplash up against "wood shiplap" that has been painted or should I put up hardie board 1st? Thank you sir.

[@は私です彼の名前]

Awesome explanation. Thank you so much!

[@bassface84]

you explained that really well. I feel like I understand it a lot better.

[@SalDiBlasi]

Thanks, glad it helped

[@observer547]

that explains allot, the idea I had is that modified thinset is way superior than unmodified thinset, when you use unmodified in previous videos made me wonder why, thanks for clearing things up. Have you ever worked in swimming pool tiling before? if you work in one please make a video because there is not much in the internet about it. Many thanks and regards from Denmark.

[@SalDiBlasi]

+observer547 I have done a few repairs over the years, but i really don't do any outside work any more.

[@observer547]

I can imagine how hard will it be, thanks for replying and best regards.

[@daviddemarsh1371]

Hi Mr. Diblasi, On a shower with a waterproof membrane such as hydrobond, would you use mod or unmod? I would think the moisture would be trapped and extend the hydration longer than desired? Thank you. Dave D.

[@SalDiBlasi]

Hydroban calls for modified. Schluter is pretty much the only one that asks for unmodified, and now that they have stated making their own thinset, you have the option to use modified as well with Schluter.

[@daviddemarsh1371]

Sale Diblasi Thank you sir. RTFD ...

[@jcmase72]

Setting cement tile over Schluter ditra would be recommend to use what type thinset?

[@SalDiBlasi]

Any Schluter brand mortar, or any other premium unmodified of any brand mortar.

[@jcmase72]

@@SalDiBlasiThanks Sal, for responding to my question. In my experience in the installation of cement tile over the ditra . It's a much better lay and more efficient for the setter with modified. I did a 16 hour test with 8"x8"s using both, the conditions were ideal. The modified was superior. That's why I asked the question. Thanks again Sal.

[@brianchv3661]

Excellent explanation

[@billyfield8984]

at the 5:40 mark,you made the comment "the dam cure that the impervious sandwiche creates only makes the thinset stronger and promotes a very tenacious bond ",I.E.the longer the drying and curring time of any morter makes said morter stronger,i get that coming from a family of masons,so with that being said,if I have the curring time to wait,14 to 21 days before grouting or traffic,can I use modified thinset on top of ditra to give me a stronger and more flexible bond between ditra and tile ? Or for that matter,use unmodified on top of ditra to level it off,let it set up for 24 hrs and then sponge it down and use modified to adhere tiles.these 2 techniques to me seem like a great way to go.Your thoughts please

[@SalDiBlasi]

I have heard that time and again, to me it seems like a waist of time effort and money. Ditra is designed to work with Unmodified thinset and it works spectacularly well.

[@steevemachine118]

But my question is...well...They say that if ANY of the 2 surfaces is porous, you should use "modified thinset". We all know that tiles like ceramic and porcelain are porous (unlike marble or granite). Should we use "modified" then?

[@SalDiBlasi]

Porcelain tile is not porous at all, and Marble and granite are mush more so, you have it backwards, the definition of a porcelain tile is actually tied to the porosity which has to be less than 0.5% . If you are going to use Schluter Products, then you should use an unmodified thinset, as the recommend, and as far as I know they are the only ones that require unmodified Thinset.

[@Chris-lz7sx]

Well explained Sal

[@brockolive5330]

Sal. For a beginner diy job do you recommend the kerdi board. I've heard that as you need to use unmodified thinset the tiles slide easily

[@SalDiBlasi]

Tiles will slide with any thinset if it is not a no sag thinset. So if you use Schluter's thinset, you can use modified for everything, that would be Schluter AllSet, or you can use their unmodified to set the tile, Schluter Set. If you use some other brand of thinset, then you need to set the tile with unmodified.

[@brockolive5330]

Sal DiBlasi That makes sense. Thanks Sal

[@mattpashley5493]

Hi sal what's the best tile levelling system mate

[@SalDiBlasi]

the one I sell dibsmart.clickfunnels.com/order-form-22471129

[@jbbrise815]

Good info. 👍

[@SharpBlockSoft]

Is there a book I can read about this?

[@SalDiBlasi]

+Serge Shariy Tile setters Bible is the TCNA handbook.

[@michaelquintana678]

is this the same as tile glue or mortar, its all the same right juts different names

[@SalDiBlasi]

Thinset is the Mortar the you use to set tile. It is not glue, and it is not all the same. Thus should help, kzbin.info/www/bejne/eHvSgXt9qdqep9E

[@michaelquintana678]

Ok thank u Sal

[@danilohermoso8560]

Great video! I am relatively new to the DIY scene. I just want to confirm that on concrete substrates, I am better off using unmodified, sanded thinset and the use of modified thinsets for concrete substrates would be more of an overkill (unnecessary additional expense) --- I would greatly appreciate it if you could comment on this. Thank you...

[@SalDiBlasi]

Depends on the tile, for porcelain I would use Modified for sure.

[@danilohermoso8560]

What about ceramic tiles on concrete substrate --- would unmodified thinset be appropriate?

[@SalDiBlasi]

I would feel better using a modified thinset, however unmodified should work. The question is not whether you can, but whether you should. It is always smart to use a higher quality adhesive and not the cheapest.

[@danilohermoso8560]

Thanks a lot for the invaluable comments. I will be following your advice when I replace next week some of our floor tiles that popped up after almost 8 years. More power to you!

[@johnmiller8528]

Sal, so you are supposed to use unmodified thinset on kerdi and ditra to install the tiles on?

[@SalDiBlasi]

Yes unmodified to set the tile on Ditra and Kerdi.

[@johnmiller8528]

www.schluter.com/schluter-us/en_US/faq/ditra-ditraxl-tile-thin-set-mortar-type

[@johnmiller8528]

sal i read differently here? ^ not saying you did it wrong, but how am i supposed to know which to use?

[@hj8607]

so if the wall is extremely(totally ) well sealed and large 12x24 tile is being applied , an unmodified med bed mortar may work best ? (or schluter set )

[@SalDiBlasi]

Schluter is the only one that calls for unmodified, otherwise it is pretty much always Modified.

[@bluekeet]

when installing kerdi membrane over drywall do you use modified or unmodified thinset to glue the membrane to the drywall?

[@hj8607]

sal wont see this question as reply to my question, however, if drywall is not sealed a modified will retain moisture for crystal formation (repost as general question for Sal's input)

[@HBSuccess]

Drywall is a horrible substrate for anything other than paint. I think it's a waste of money to put Kerdi membrane on drywall. Replace the gypsum board in the tiled area with cement board (Durock)- tape/thinset the joints and don't worry about the membrane. Just my .O2 - YMMV

[@ronnash3827]

Nice work. I enjoyed the explanation.

[@SalDiBlasi]

Thanks Ron, Might be time to update this video with all the advancements in the last few years.

[@ronnash3827]

Sal DiBlasi there’s definitely some new chemistry in the mix.

[@SalDiBlasi]

@@ronnash3827 Maybe feature some Laticrete Thinset Mortar.

[@I.c.k.c]

Is it possible to use Portland cement mixed with sand , like the old timers ?

[@SalDiBlasi]

No, don't do that.

[@I.c.k.c]

Sal DiBlasi why would it be bad to do that ?

[@oWhiteMonster]

Would Portland cement shrink 🤔

[@bart_seavey]

If you're installing tile in a climate controlled house, modified thinset will work fine. Note that Redgard, which can be used to provide a waterproof shower pan, recommends use of modified thinset on top of it. The problems associated with modified thinset on top of Ditra are greatly exaggerated. It's only a problem outdoors in highly humid areas, where you are grouting next day. I used modified thinset on Ditra. Worked superbly. Wait a week or two to grout and you'll sleep fine.

[@SalDiBlasi]

If you want to keep the manufacturer warranty, then use what the recommend, if you don't care about it then use what you want.

[@bart_seavey]

Understood, voiding in the warranty is on me. I only used one roll of Ditra for a small bathroom with 12x24 ceramic tile on the floor and shower. If it failed, I'll have bigger problems than worrying about getting my $86 back for the Ditra. Redgard's own uncoupling mat membrane, which is waterproof and vapor proof, recommends use of modified. And I also live in an extremely low humidity environment and waited 2 weeks to grout. All told, I figured the likelihood of the modified failing was remote in comparison to its benefits.

[@bart_seavey]

Further from Custom Building Products: "There is a misunderstanding that a polymer-modified mortar will not cure under porcelain tile when installed over an uncoupling membrane. This is not true. The hydration of the Portland cement and increased mortar strength will occur whether it is exposed to air or in a sealed container. " www.custombuildingproducts.com/media/60712310/tb85-uncoupling-membranes-and-polymer-modified-mortars-in-tile-installations.pdf

[@SalDiBlasi]

I don't debate whether it will work or not, but if you use a product, the manufacturer recommendation always trumps any other requirement. If you use Schluter, then use the products they say to use, if you use Redgard, then use the products the say should be used. If the warranty means nothing to you, that is also fine.

[@bart_seavey]

I don't disagree with you. I would feel the same way from a liability perspective if I were working as a pro. But I think the science on this topic is worthy of being explored more. I don't think there is any evidence that modified thinsets require air to cure and do not experience the hydration process, albeit slower. As it is, the smart guys who sit on the Tile Council of North America (TCNA) recommend using a polymer-modified mortar meeting ANSI A118.4 or A118.15 when installing ceramic tile over a waterproofing membrane. This and Custom Building Products advice seems to be at odds with Schluter's requirements to maintain the warranty.

[@outonthetiles599]

Hey Sal, I heard a contractor mention something about how thinset can become "detempered" if it's not mixed correctly, resulting in a fail. I didn't quite catch it, but it was something to the effect that after letting it slake if you realize you need to add more thinset powder to the water to stiffen the mix it will cause a fail. LIkewise if you add more water to the mix to increase the soupiness of it. Is this right? Is it generally ok to add either water or thinset powder when mixing as long as it's done before letting is slake?

[@SalDiBlasi]

The guy is actually correct, once the thinset has slacked, it should not have water added to it, or powder. If has been sitting in the bucket a bit and starting to get a bit stiff, it can be spun with the mixer to loosen it up, but don't add anything to it.

[@outonthetiles599]

One other thing I've heard conflicting ideas about is which to add to the bucket first: Water or thinset. I've noticed that adding the powder first then water can cause clumping and throws up excessive powder "clouds" which obscures the view of the inside of the bucket making it harder to mix correctly. I see you added the water first in the video which answers my question, but just wanted your take on if there is ever a time when the powder should be added first.

[@SalDiBlasi]

I always add the water first, but as long as it is thoroughly mixed, it can be done either way, the water first does make it easier.

[@outonthetiles599]

Hey Sal, it's good to know you're here, educating. I've come a good ways thanks in great part to your video productions. I decided to join NTCA after viewing several of your vids on the subject. Best decision I ever made. Carlos Collazo

[@SalDiBlasi]

Well then, you need to become aTile Geek facebook.com/groups/TileGeeks/?ref=bookmarks

[@cornfusedatbest6693]

QUESTION: Is there a shelf life to to Thinset? (non modified)

[@SalDiBlasi]

Yes all cement based products have a shelf life which is usually about a year, look at your package most will have a date of manufacture.

[@cornfusedatbest6693]

Thank you for the quick reply. I think I may be about 3-4 months past, the date is illegible .. SAL , am I screwed or what?? If so, what are my options? Again, Thank You for responding so quick.

[@SalDiBlasi]

Why take a chance, buy new materials.

[@cornfusedatbest6693]

...no Sal, guess you didn't get the "SCREWED" part , I already put it down on my IN-LAWS counter top. HENCE: OPTIONS????

[@SalDiBlasi]

Wait and see, you will probably be fine.

[@HBSuccess]

I use MODIFIED thinset 99.9% of the time.... years ago it was always via latex or acrylic additive (liquid)... today I've been using Flexibond and mixing with water. But since Schluter products are tough to get where I work... I'm normally installing over Durock, using Redguard in wet areas - and just cementitious board (usually 1/2 Durock- ALSO thinset with modified... in other areas. Seems to me Durock + Redguard is about the same thing as Schluter/Kerdi in that there's no place for the moisture to go. But I've never had any issues- I wait a few days before grouting anyway so does not matter how long the dry time is for the thinset.... and I've never had problems on shower walls using MODified Thinset over Redguard. . So... are you saying it's A-OK to ignore Shluter's requirements to use UNmodified Thinset and use modified anyway on Kerdi? Like others - while I appreciate the building science.. hydration/crystals/etc..... but I am confused whether or not modified thin-set can be used with Schluter products. Can it ? Thank you Sal.

[@SalDiBlasi]

All the other manufacturers say to use modified when going over a liquid applied waterproofing membrane, so they do not consider it to be a problem, schluter specifically wants you to use unmodified over ditra or kerdi, unless you are using Schluters own thinset which was not available when this video was made. kzbin.info/www/bejne/bX-VnGSIo9KYgKs So follow manufacturer recommendation if they call for modified, then use modified, if they call for unmodified then do that. It should also be noted that there have been advancements in Thinset technology which enables a chemical cure allowing for thinset to dry without the need for evaporation, so there are many new thinsets that have this ability.

[@raptureready9502]

@@SalDiBlasi would you use modified or unmodified under the cement board? Under the cement is the subfloor 3/4" osb

[@SalDiBlasi]

@@raptureready9502 Modified.

[@raptureready9502]

@@SalDiBlasi what about under the tile? Tile is 6"x24"

[@raptureready9502]

Porcelain tile