How to Mix Small Batches of Thinset Mortar

At last, mixing small batches of thinset doesn’t have to be a secret!

Finally, you too can know the exact amount of water and thinset powder to add together to get the perfect thinset consistency.

This means:

• No more wondering what “peanut butter consistency” looks like
• No more struggling to gauge how much a half of a bag of thinset powder is
• Too-thin and over-watered mixtures are a thing of the past

Rather, this post explains how to mix the right amounts of the proper ingredients every time.

Estimated reading time: 7 minutes

One formula for proper thinset consistency

It’d be nice just to have one formula that covers every mortar. For example:

• 4:1
• 2.25:1
• 4lbs for every quart of water

But it doesn’t work that way. I wish that it did.

In fact, that 4 to 1 ratio for hand mixing thinset is found elsewhere on the web. But it’s wrong. In fact, I have yet to find one thinset that this ratio works for.

Alas, I had to abandon my dream of having one super-formula and came to the realization that this post was going to be a lot more work than I had planned.

Every Thinset is Different

Instead, I found myself buying about a dozen different thinsets. Then I would carefully measure how much powder I would have to add to 1 quart of water to get the proper thinset consistency.

All the while recording each individual product’s powder-to-water ratio in a chart. See chart below.

How I did it

Here’s how I came up with my water/thinset ratio chart:

Weight vs Volume when mixing thinset by hand

My first thought was to go by weight. I even purchased a special food scale that I wouldn’t mind getting dirty in my garage.

However, what I have found is that mixing mortar according to volume yields better results than trying to weigh the mortar.

It used to be that every bag of thinset weighed 50lbs. But, now they have lightweight mortars that substitute different materials for traditional sand. Therefore, this means that the substitutes weigh less.

Consequently, I had bags that weighed:

• 50lbs
• 44lbs
• 40lbs
• 30lbs
• 25lbs

However, all the bags are similar in size and when the bag of thinset mortar is mixed they should all yield a similar amount of product.

Mixing small amounts of thinset by volume

This method had its challenges, as well.

For example, I would measure 1 qt of thinset powder and dump it into a larger measuring container which then showed it as less than 1 qt.

As a result, this meant that the measuring containers weren’t directly compatible.

What I ended up doing was using a small 1 qt container for measuring all powder and another container with a pouring spout for measuring quarts of water.

How to Mix Small Batches of Thinset Step-by-Step

Tools needed

The tools are pretty simple for this. Here’s what I used:

• Margin trowel
• 2 measuring containers
• Bucket to mix everything in
• Optional: drill with a mixing paddle

Two measuring containers are useful so you can use one for water and the other for powder. Consequently, if you use the same container for both the thinset powder would stick to the damp container.

Additionally, you want the container used for measuring thinset to have clear, individual ounce increments.

Mixing thinset in small batches

Once you get the measuring sorted out then you just follow the basics of mixing thinset mortar.

Exact Batch Thinset Cheat Sheet

Below is my chart which contains exact ratios for different thinset products. These products include:

• Custom Building Products: Versabond, Versabond LFT, Prolite
• Laticrete: Trilite, 253 Gold, Multimax Lite
• Mapei: Porcelain Tile Mortar, Ultralite Mortar, Ultralite Pro, Ultraflex LFT SG, Keraflex Plus
• Schluter: All-Set

Why these mortars?

I was looking for mortars that are widely available in retail stores. In fact, all of these products were purchased at either Home Depot, Lowes, or Floor & Decor.

Further, these products are very popular and range in use and performance. All are modified mortars meeting A118.11 and A118.4 at least. Some meet A118.15 as well.

Also, this list will continue to be updated over time. Do you have a thinset that you would like to see on this chart? List it below in the comments.

Finally, I have a post that details what Home Depot thinsets you want to buy, if you are interested.

Fine-tuning the consistency of the thinset

Inevitably, there is bound to be some variance in the way that two different people measure and mix the ingredients together.

• If you find that your mixture is too thick try adding 1-2 additional ounces of water to the mixture. Make sure to add the water early in the mixing process.
• On the other hand, if you find that your mixture is too thin then try adding 2-4 additional ounces of thinset to the mixture.

Thinset Consistency

Here’s a gif of what the mortar consistency should look:

The Exact Batch ratio is the best thinset-to-water ratio that I found that gives optimal results for thinset consistency. These are not calculations based on the manufacturer’s data. Every mortar was individually mixed until it was a desirable consistency.

• The figure in the cell is the number of ounces of thinset powder
• That number gets added to 1 quart (32 ounces) of cool, clean water
• ratios can be doubled, tripled, or quadrupled as you desire

How many tiles can you install with this amount of mortar?

• I found that I could get 5-7 sq. ft of 12×24 large format tile installed using a 1/2 x 1/2 inch square notch trowel and back buttering the backs of the tile
• I would imagine this would allow you to get 10 sq. ft. using a 1/4 x 1/4 inch notch trowel. So, if you were installing subway tile or backer board, for instance.

FAQ for mixing small batches of thinset by hand