Premixed Thinset For Shower Walls (Is It The Best Option?)

Premixed thinset is very popular amongst DIY enthusiasts. Unlike traditional thinset mortars, premixed thinset is a no-mess and no-mix alternative.

After buying it, all you need to do is pop the lid and start using it to install tiles. However, apart from its ease of use and convenience, there are some arguments that premixed thinset isn’t the best option to use on shower walls.

If you have also stumbled across these arguments and would like to know whether premixed thinset is recommended for shower walls, here is a comprehensive guide on all you need to know.

Premixed thinset

What are Some of the Problems Associated with Using Premixed Thinset on Shower Walls?

Over the years, contractors and homeowners have run into a couple of issues when using premixed thinset on shower walls. Some of these issues include;

• Premixed Thinset Doesn’t Have the Best Water-Resistance Capabilities

Showers are categorized as high moisture areas. The walls are constantly wet. Therefore, any product you use on them must be water-resistant. Otherwise, your walls may deteriorate due to water damage, and mold may grow.

Unfortunately, premixed thinset isn’t as water resistant as other alternatives. Over time, moisture passing through the tiles soaks into the premixed thinset and it slowly breaks down. As time goes by, it will weaken, and the tiles may start to fall off.

Considering how wet shower walls may get, premixed thinset won’t last very long. Therefore, it’s not the ideal type of thinset to use on shower walls.

• Premixed Thinset Takes Too Long to Cure

Tile installation is a pretty complex project. You may prefer to use premixed thinset because it doesn’t set too quickly, as is the case with powder thinset. However, this feature can be a double-edged sword.

When thinset takes too long to cure on your shower walls, and you unknowingly introduce moisture into the room. The curing process can be significantly affected. Therefore, the premixed thinset can fail.

• Premixed Thinset is Expensive When Used on Large Projects

Besides not having the best water resistance and taking too long to cure, premixed thinset also costs way more than powder thinset.

On a small shower, you can use premixed thinset without breaking the bank. But on big showers with significantly sized walls, you will pay more for premixed thinset as compared to the regular stuff. From a price point of view, premixed thinset isn’t ideal for big showers.

How to Remove Premixed Thinset from Shower Walls?

In case you or a contractor has recently installed tiles on shower walls using premixed thinset, and you have just come across this article, there are two ways you can deal with this problem.

Over the years, I have seen several projects where premixed thinset was used on shower walls, and it lasted for a while. However, eventually, the premixed thinset always absorbs moisture, the tiles come off, and mold grows on the shower walls.

You can either let the premixed thinset cure. Give it at least a week before you can use the shower. But the tiles won’t hang on to the shower walls for long.

On the other hand, you can pour some warm soapy water on your shower walls and scrub off the premixed mortar with a bristled brush. The same should also be done to the tiles.

Premixed mortar comes off easily. And this shouldn’t be difficult. Then you can install the tiles using powder thinset. You can replace the tiles that still have some traces of premixed thinset.

Understandably, many homeowners are reluctant to remove premixed thinset from shower walls because it’s tedious. But isn’t it better to remedy this mistake now than wait for tiles to fall from your shower walls a year or two later?

Can You Use Premixed Thinset on Shower Walls with a Kerdi Membrane?

It’s not unusual to find a Kerdi membrane on a shower wall. This waterproofing sheet keeps moisture from your shower walls and is also a suitable tile substrate.

If you have installed Kerdi on your shower walls, please don’t use premixed thinset to lay the tile. Schluter, the manufacturer of Kerdi, is very clear about this matter.

Schluter only recommends that their systems be used with their Schluter SET or an unmodified thinset mortar.

You need to keep this in mind if you have Kerdi on your shower walls. Going against Schluter’s recommendations voids the warranty and may result in tile failure.

Why Do Some Contractors Recommend Premixed Thinset for Shower Walls?

If you are an active member of several online forums, you can testify that most people only have negative things to say about the use of premixed thinset on shower walls.

At the same time, there are a couple of contractors who swear by using premixed thinset on shower walls. In such a situation, you may be confused and unsure of which path to follow.

What you have to understand is that just because a contractor recommends a particular product, it doesn’t always mean it’s the best option. Premixed thinset such as mastic should be kept away from high moisture areas like shower walls.

The reason a contractor can recommend premixed thinset is that it’s easy to use on shower walls. After all, there is no mixing involved. On their end, they will have saved a lot of time and effort.

But as the homeowner, premixed thinset won’t last for long. As we have seen earlier, it’s far from being considered water-resistant and takes too long to cure.

It would be best if you let your contractor know about the drawbacks of using premixed thinset on shower walls. And if they don’t follow your advice, you should hire another contractor.

Besides contractors, some premixed thinset manufacturers claim that their product can be used on shower walls. These are usually marketing gimmicks designed to convince uninformed buyers.

What Should You Use to Install Tile on Shower Walls?

Now that you know the drawbacks of using premixed thinset on shower walls, you may be left wondering – what is the best tile adhesive to use on shower walls? The good news is that there are a couple of options worth considering.

First, we have powder-based thinset mortar. This is the regular type of thinset which contains Portland cement, sand, and water.

Even though it’s messy and tiresome to mix, you are assured of a high level of resistance to moisture and strong adhesion to the shower walls and tiles. Cement-based thinset doesn’t expand nor contract and is a suitable substrate for tile.

If you prefer another type of mortar, you can use epoxy thinset. This comprises a powdered filler, resin, and hardening agent.

These three should be mixed before the product can be installed. Epoxy mortar also creates a strong bond between tiles and shower walls.

It is water and mold-resistant. However, it dries very quickly. Therefore, it’s primarily popular amongst professionals than Do-It-Yourselfers.

Are There Any Benefits of Using Premixed Thinset on Shower Walls?

Apart from the drawbacks, there are several benefits of using premixed thinset on shower walls. For instance, there is no mixing involved. That makes the job pretty easy.

Also, premixed thinset comes with a pretty workable consistency. Rarely will premixed thinset run on vertical walls and cause a mess in your shower.

However, the drawbacks of using premixed thinset on shower walls outweigh the advantages. You shouldn’t use it, yet there are plenty of options out there that are much better.

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