How to Mix Thinset Mortar

Thinset Mortar is Ideal for Moderate to Heavy Traveled Ceramic Tiled Floors

By Mark J. Donovan

Thinset is a mortar based adhesive used to set interior and exterior ceramic tiles. It is typically mixed with water or an acrylic additive. There are a variety of types of thinset mortar to choose from so it is important that you select the right one for your particular tile project. Thinset mortar is also available in gray and white colors.

Thinset mortar is different than organic mastic adhesive. Thinset mortar is made from Portland cement and fine silica sand which when mixed with water produces a concrete hard surface that is not susceptible to moisture.

Organic mastic adhesive on the other hand is slightly spongy and can absorb moisture. Consequently thinset mortar should be used on moderate to high traffic ceramic tile floor areas, and in wet areas such as shower stalls. Organic mastic should be limited to walls, countertops and lightly traveled ceramic tiled floors.

To ensure a solid bond between the tile and tile base it is important to know how to mix thinset mortar properly. If mixed properly, thinset mortar should have the consistency of peanut butter or a thick pancake batter.

How to Mix Thinset Mortar Properly

To properly mix thinset mortar you will need a dust mask, bucket, paddle mixer and paddle. The paddle mixer and paddle can be substituted with a hand trowel or rugged mixing knife if you have a small ceramic tiling project.

To begin the mixing process, pour water or an acrylic additive into the bucket such that it is about one quarter full. Then pour the dry thinset mixture into the bucket. Note, do not pour too much of the thinset into the bucket to begin with.


With the thinset added to the water (or acrylic additive), insert the paddle into the bucket and begin to mix the thinset and water slowly. Work the paddle up and down, starting from the bottom of the bucket. Continue this process until the thinset is thoroughly mixed. If the mixture is too loose add more thinset to the solution and repeat the process of mixing.

Alternatively use your hand trowel or mixing knife to mix the water and thinset mixture together.

When the thinset mixture has the consistency of peanut butter let it rest for 5 minutes.

After letting the thinset mixture rest for a few minutes, mix/stir the solution again for another 5 minutes.

With the second round of mixing complete, your thinset is ready for use.

How to mix thinset mortar

One final note: It is important mix up only enough thinset mortar to support about 20 minutes of tile setting work. Thinset mortar will begin to harden, or set, within 20 minutes and it is unwise to apply more water to thin it out. Thinning out mortar that has already begun to set will create a weakened thinset mixture and could potentially lead to loosened ceramic tiles down the road.

For information on installing a shower pan membrane liner for a ceramic tile shower, see the Shower Pan Membrane Liner Installation Ebook from  The Shower Pan Membrane Liner EBook will quickly teach you the step-by-step process for installing the shower pan membrane liner correctly. It includes instructions on framing the shower stall, pouring the pre-slope and shower base mortar, and installing the shower pan membrane liner.

See’s Ceramic Tile Calculator

See my “How to Tile a Custom Ceramic Tile Shower” Ebook to learn how to tile your own shower:  For a detailed set of instructions on tiling a shower floor and walls, including pictures for every step in the process, see my “How to Tile Custom Ceramic Tile Shower Ebook”.

Related Information

Additional Ceramic Tile Resources from


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