Modified Or Unmodified Thinset Over Redguard

Modified Or Unmodified Thinset Over Redguard- Answered


You’re thinking of tiling your walls and making it waterproof. So you chose to apply redguard.

But now you’re not sure if you should use the normal thinset or the modified one.

So, should you use modified or unmodified thinset over redguard?

Redguard exclusively recommended a modified thinset to be used with it. Alongside that most waterproofing jobs need modified thinset to be used. Unmodified thinset is used in rare cases where you’re using ditra or any other impervious membranes under the tile. But modified is the most used thinset.

So, that’s the gist of it. But to get a better comparison you need more information. And that’s what we are here for. Here in this article, we explore those differences in detail for you to make a decision.

So let’s get started!

Quick Comparison: Modified or Unmodified Thinset to Use With Redguard?

When you’re tiling your bathroom, using a thinset is a common practice. There are mainly 2 types of thinset available in the market. 

Modified and unmodified are the two types of thinset. And they have their own use case and have their pros and cons.

If you are tiling, there are some other factors too that you need to consider. 

Some people might need to install ditra if they have an even surface and load-bearing surface. Ditra is great for vapor management and load distribution and lots of other stuff.

Also, you can use ditra on your walls and floors. It can come in handy if you are looking to hide your bedroom sink.

Or your importance could go to waterproofing the area you want to tile. For example, you want to tile your shower. The shower area needs to be tiled and waterproofed underneath.

So that water doesn’t seep in and make your walls damp. And to do that you can use redguard coating to waterproof. But if you choose redguard then you need to choose your thinset according to that.

To fully understand what kind of thinset is best for you we need to see the difference between them. That’s why let’s have a look at a quick comparison table.

FactorUnmodified ThinsetModified Thinset
Portion Of Application Has to be spread in thick layersNeeds to be used in thin neat layers
Water Retention CapabilitiesMuch lower than modifiedHigher than unmodified, allows better curing and strong, sturdy bond
Additional Compounds In MixtureNothing extra. A blend of Portland cement, sand, and water retention agents.Has powdered or liquid latex polymer added to it to increase water retention and strengthen the bond with a small amount of application
ANSI Code For IdentificationA118.1 covers all sorts of unmodified thinsetHas multiple ANSI codes, with long numbers following after A118.1
Advised To Use WithTile installation with ditra, in even surfaces which are load bearing.Should be used where you need a waterproof coating like redguard.

Well, this table clearly paints a picture of the basic differences between unmodified and modified thinset. But to completely understand where you should use them, you need to know in detail.

Because even though unmodified thinset is older and less developed. It still has wide use cases and a relatively good market share.

So let’s discuss the differences in detail to get a clearer viewpoint.

Modified Vs Unmodified Thinset: A Brief Discussion on Differences & Varied Use Cases

Unmodified thinset has been used for a long time. This was the only thing you could use before chemical engineer Henry B. Rothberg developed the modified thinset.

He was looking for a solution that could minimize the use of thinset. But it will result in a much stronger bond between the subfloor and the tile.

He first tried adding rubber to the thinset mixture. Which worked but had a much smaller shelf life. Then he tried a lot of complex chemical combinations. And finally figured out a latex mixture and launched laticrete.

Nowadays modified thinset is widely used in tile installation. Even though a modified thinset is the upgrade over an unmodified thinset, there are lots of cases where an unmodified thinset is the way to go.

So let’s explore their differences in detail so we can understand where they need to be used. So that we can decide if our project needs to be modified or unmodified thinset.

Difference in Application

The most basic difference can be seen in the way these two need to be applied. The reason the modified thinset was developed is that it had to be spread out nearly 2-3 inches thick to perfectly work.

Also, thinset mortar needs time to cure and bond properly. The ratio of the amount to the strength of the bond wasn’t also very efficient.

Developing the modified thinset, the application changed a lot. It could be spread only 1-1.5 inches thick and it would still form pretty strong bond.

Also, it had way better water retention capabilities due to the added latex. So it can now store and cure with way more water and make very strong bonds.

Identifying the Thinsets: Contents and ANSI Code

Thinset is normally Portland cement, mixed with sand and some water retention agents. The difference between modified and unmodified thinset is. Modified thinset has some latex additives along with the other contents.

That latex additive gives it more water retention capabilities. And makes it bond stronger with smaller applications.

The liquid latex polymer is added to the modified thinset mix. Or it is in the powdered form. Which makes the application more convenient.

Also, you can identify the different thinsets by their ANSI codes. The American National Standard Institute issues different numbers for unmodified and modified thinset.

The number A118.1 mostly covers all the unmodified thinset there is. But if your thinset is modified then there will be a longer number following this number. 

And sometimes there can be multiple numbers on the pack. If there are different latex materials used in the thinset.

Various Usage Scenarios

This is the most important part of our discussion. And mainly why we are having the discussion in the first place.

Even though they are basically an upgraded version of the other, they both have equally important use cases.

While installing ceramic tiles or cement tiles, we most times install other accessories between the tile and the floor.

If you are installing any impervious installation membrane under your tile, your best bet is to use an unmodified thinset. Because that does not deprive the thinset of moisture so it gets plenty of time to cure and get strong.

Meanwhile, if you’re shopping for an impervious membrane for your floor, here are some options you can choose from


Hope this makes your home improvement journey a bit easier for you!

Also if you’re installing ditra on an even surface of load-bearing structures, here unmodified thinset is also recommended. These recommendations are most times made by the manufacturing companies themselves.

If sometimes the surface is not even but you need to use unmodified thinset you might need to use self-leveling compounds. But sometimes self-leveling compounds refuse to be flat, and you need to take care of that.

But if you are using redguard or any kind of waterproofing material in between your wall and tile. Then in these cases, modified thinsets give the best results.

Redguard company specifically states that they are better compatible with modified thinset. So that clearly shows that if you are applying regard, you need to use modified thinset.

This discussion has all the necessary points explained quite well for you to make a decision. Now the rest is up to you to figure out which one is for you. We can offer our verdict, but the final decision is yours.

Final Verdict

Modified thinset is clearly the better version. And it is widely used in tiling and other sectors for its advantages.

However, there are specific cases that require unmodified thinset as well. And you need to identify which one is applicable for you.

If you are tiling or flooring and using impervious membranes, install radiant floor heating. It’s best for you to use unmodified thinset.  As that gives the thinset enough time to cure properly and bond strongly.

And in most other cases, and especially when you’re using any kind of waterproofing system you need to use modified thinset.

If you are tiling your shower area or kitchen area, which will get wet more often. You need to use redguard to save the floor or wall underneath from potential leakage.

You need to apply redguard in between the floor and the tile. But you can waterproof drywall directly as well. But it’s not a good idea to use waterproofing paint like drylok directly over drywall.

And redguard specifically named modified thinset as a recommendation for usage. So if you are going to tile over redguard, you need to use modified thinset.


How To Know If Your Redguard Has Dried Properly?

You’ll know if the redguard has dried properly or not by looking at the color. Redguard is a waterproofing substance that you spread like paint. It is applied in between the floor and the tile. It’s bright pink in color when applied. You’ll understand that it has dried completely when it turns red.

Can You Substitute Cement Board With Ditra?

Yes, ditra is a quite viable substitute for cement board. It’s much better at water resistance and is very durable. As it does not change shape or warp at all in presence of moisture. But the only setback is that it is more expensive than a cement board. 

Can You Use A Damp Proof Membrane Under Floor?

Yes, you most certainly can. Damp-proof membranes are very good at keeping moisture from ruining your walls. You can install them on your wall and under the floor too. Most people use them if there is any dampening in the walls. But you can use them before building your home for protection beforehand.

Wrapping up

Hopefully, that settles if modified or unmodified thinset over redguard. It’s best to prepare your home for future mishaps, rather than fixing it after one. And always let a professional handle the job.

Until next time, have a great day!

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