If you’re planning a tiling project, whether it’s a bathroom renovation or a kitchen backsplash, choosing the right adhesive is a crucial step.

There are a few different kinds of thinset and which one you’ll use varies based on your project. Each has its strengths (literally), meaning the choice depends on your specific project needs.

So, let’s break down the different types of thinset mortar—modified, unmodified, pre-mixed, and powdered—so you can understand when to use each for your next DIY project.

What is thinset?

Thinset is a kind of cement-based adhesive to bond tiles to surfaces like cement board, drywall or concrete. It’s made up of Portland cement, sand, and bonding agents and when it’s mixed with water, it creates a strong bond as it cures.

Thinset comes in two main forms: unmodified and modified, and there are also pre-mixed and powered versions of each.

We’ve used just about every kind in our projects over the years so let’s do an overview of each and when to use ’em, with the caveat that you should always check any specific directions on your tiling products!

Unmodified Thinset 

This is sometimes also called “dry-set” mortar and is made up of the same Portland cement, sand, and bonding agent mix as modified thinset but it doesn’t have the polymers and additives. It hardens as it cures and creates a really strong bond, but because it isn’t as flexible and high performance as modified thinset, it requires a few specific conditions/installations.

When to use:

Over Schluter or other Waterproof Membranes: Unmodified thinset is often recommended for these types of installations because modified thinset takes a long time to dry especially between waterproof layers like on those membranes.

In dry areas: Unmodified thinset isn’t as water resistant as the modified kinds, so it’s best suited for places like a kitchen backsplash or laundry rooms or a wet bar, etc. where there won’t be significant moisture.

Basic substrates: A substrate is the name for the material underneath the tile (AKA cement board, drywall, etc.). This kind of thinset is best over concrete or cement backer board, not something a little more iffy like drywall or OSB or plywood that might soak up some of that moisture too quickly as it dries.

Modified Thinset

Like we said above, modified thinset is the same as unmodified but it’s got polymer additives to enhance it (like latex), that work to make it more flexible, strong, and water resistant.

Those additives help the modified thinset stick to a wider range of surfaces and keep a strong bond. This is especially important in situations where you need high performance like a bathroom (because nobody wants tiles falling off their shower wall!).

When to use:

Outdoor projects: Patios or walkways (or outdoor kitchens like ours!) are a good place to use modified thinset because they can handle the fluctuations of the environment out there, like when base materials expand and contract.

Bathrooms: Shower walls and floors or any other area prone to water exposure.

Non-cement backers: If you’re tiling over a surface like plywood, this could be a good option because again, it can handle the expansion and contraction of that surface. It’s also a good idea for large format tiles!

The downside is that there’s usually a longer cure time, so keep that in mind when you’re scheduling out your timeline.

Pre-Mixed vs. Powdered

Pre-Mixed Thinset

This is just as it sounds: it comes in a tub that’s ready to go already mixed so you can just chuck your trowel into the tub and start tiling.

The benefit of pre-mixed thinset is that it’s great for beginners who maybe aren’t as familiar with the proper consistency of thinset or are worried about being able to mix different batches together well. The downside is it’s significantly more expensive so would be better for your first tiling project or a small area.

The convenience is really its main selling point, and can be a good option when you’ve got limited time or need to stop and start a project (like when you’re working in a kid’s nap time).

Pre-mixed isn’t recommended for outdoors or high moisture, though.

Powdered Thinset

Powdered thinset is more traditional and is the kind of thinset where you mix it with water to activate before you start tiling. You definitely get more control over the consistency and the amount you need, but like we said above, if you’re a beginner and if you’re not needing an entire bag at once, adjusting the water-to-powder ratio can be a pain.

On the flip side of that, though, you do get full customization in being able to control how much you make, the thickness, etc.

Like for example, you might want to make the thinset going on a shower wall a little thicker than you would for the floor so it doesn’t all work against gravity and fall down the wall (ask me how I know).

You can also find powdered thinset available for just about any application and substrate so it’s super versatile.

We’ve used both thinset types numerous times for various DIY projects and now go for the powdered stuff 99% of the time, but like we said, each one’s got its pros and cons!

For instance, when we were doing our outdoor patio makeover we used a powdered thinset that we mixed due to the large surface area we had to cover — powdered thinset can cover a larger surface area — but on our laundry floor we used pre-mixed because we only had small increments of time to work in and not a lot of surface to cover.

Powdered Thinset Mixing Tips for Beginners

Mixing powdered thinset might seem daunting if you’re new to tiling, but it’s easier than you think.

The most important step is to follow the manufacturer’s recommended mixing ratios to ensure a strong bond. Adding too much water will weaken the adhesive, while too little will make it hard to spread.

Start with less water, adding more gradually until the mixture has a smooth, peanut butter-like texture. For the best results, always use a mixing paddle to ensure an even blend.

Note: Always add the water to your bucket first, because if you do powder first it’ll be so much harder to mix and you’ll probably have clumps at the bottom.

Pre-Mixed vs. Powdered Thinset Shelf Life

One factor to consider when choosing between pre-mixed and powdered thinset is shelf life. Pre-mixed thinset has a shorter shelf life once opened because it begins to dry out.

In contrast, powdered thinset can be stored indefinitely as long as it remains sealed and dry. This means that if you’re not planning to use all of the adhesive right away, powdered thinset might be a better choice for long-term projects.

Alternatives to Thinset

If thinset isn’t quite right for your tiling project, there are a few alternatives worth considering. One popular option is MusselBound, a peel-and-stick adhesive mat that simplifies the tile installation process by eliminating the need for mixing and drying time. It’s mess-free installation, but is not as forgiving because you can’t wiggle a tile if you need to once you’ve adhered it. We used it in our kitchen backsplash and wrote a full breakdown here.

FAQs: Pre-Mixed vs. Powdered Thinset

So, what kind of thinset should you use for your project? It depends on the specifics of what you’re working on. For small, indoor projects or beginner DIYers, pre-mixed thinset is convenient and easy to use. But for larger areas, outdoor projects, wet areas or anything involving heavy tiles, powdered thinset is the better choice due to its strength and versatility.

Here are some other FAQs when it comes to pre-mixed vs. powdered thinset:

How do I achieve the correct consistency for thinset when tiling?

Imagine you’re spreading peanut butter on your favorite sandwich. That’s exactly what you’re going for with powdered thinset! You want it thick enough to stand its ground, but not so stiff that you’re wrestling with your trowel. The secret? Add water bit by bit as you’re mixing. Trust me, a little patience here pays off big time in the long run!

How do I store different types of thinset?

If you’ve gone the pre-mixed route, think of it like that fancy face cream you splurged on – seal it up tight and keep it cool. You don’t want it drying out on you! For the powdered stuff, keep it away from any dampness. Stash it in a dry spot, either in its original packaging (if you can reseal it) or pop it in an airtight container.

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