How to Mix Thinset Mortar

Thinset mortars are great for installing tile floors, because they can handle a great deal of weight and are very durable. They can be used in wet areas or high-heat areas. You buy it in powder form and mix it with water. Some thinsets are mixed with an acrylic additive so pay close attention to the instruction given with the mortar you purchase. 

What you will Need 

  • Thinset Mortar
  • Respirator
  • Large Bucket
  • Water (or acrylic additive)
  • Margin Trowel
  • ½ inch drill with mortar-mixing paddle (Optional)

Mixing the Thinset Mortar

Step 1

Start by pouring the water into your large bucket. It’s important to put the water in first to cut down on the amount of dust. Regardless, you should always wear your respirator to prevent accidentally inhaling the mortar dust. 

Step 2

Pour in the appropriate amount of powder for the job and start mixing it in with your margin trowel until all the thinset mortar is worked in and moist.

Step 3

You can either continue to use your margin trowel or use a ½ inch drill with mortar-mixing paddle to speed up the mixing process. Run your drill at a very low speed. This will prevent air from being trapped in the mortar, which makes the bond weaker. 

Step 4

Mix your thinset mortar and water until it has the consistency of a thick peanut butter. Don’t be afraid to add more water or mortar to get it right. The consistency is very important. You know you have it right if the mortar on your trowel doesn’t drip off but can be shaken off.

Step 5

Lastly, let the mortar sit for 10 minutes before using it. This is referred to as slaking and it gives the additives enough time to become activated. It also ensures all the powder is sufficiently moist. Once 10 minutes has passed, give it one last stir and your thinset mortar is ready to go. Learn how to install ceramic tile here.