How Thick Should Thinset Be for Tile?

There are different kinds of mortars. When it comes to floor tiles, mortar thinset (or simply thinset) is the one you must use. But there are also various types of thinset.

One good strategy is the use of thinset mortar to suit the tile’s warpage. Yet, you must get the right tile mortar thickness, otherwise, you’ll have an imbalanced structure. And this depends on the type of materials you’re using and the required height of the tiled surface. 

But just how thick should thinset be for tile? How do you choose the ideal size? Keep reading to find answers to this question and more.

It Should Be Material-Specific

The first thing you need to consider is the material your tiles are made of. Each kind of mortar thinset is best for a particular material.

Dry-Set or Unmodified Thinset Mortar

This mortar contains sand, water, water retainers, and portland cement. The water retainers help keep the mortar even more hydrated as you mix it with water.

This mortar works with most kinds of tiles, but the substrate has to be leveled already – the thin mortar layer will not be enough to even the surface.

For this particular thinset mortar, you need a substrate layer that is ¼ inches thick. This will ensure your tiles get embedded into the mortar. Also, the thinset’s thickness will enable the tiles to level up to the substrate.

portland cement

Modified Thinset Mortar

Modified thinset mortars have water retainers, sand, and water. They also have portland cement and a polymer. The acrylic polymer improves the mortar’s adhesion. As such, it works better than unmodified mortar for thinner tiles. The same is true if you’re sticking them to cement or other surfaces that, depending on various factors, could shake or crack the tiles.

It also makes the mortar waterproof. Yet, it makes it resistant to the freeze-thaw cycle. For this mortar, the maximum thickness should be 3/16 inches.

Epoxy Mortar

If you need more chemical resistance and strength, use an epoxy mortar thinset. Use this thinset for your resin-backed stones. Epoxy mortar contains silica sand, a hardener, and a resin.

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For epoxy mortar, you should use a minimum thinset thickness of 1 inch and a maximum thinset thickness of between 3 to 6 inches, based on your product. This thickness is suitable for tiles in commercial kitchens and harsh environments.

It Should Be Tile-Type Specific

Different types of tiles need specific thinset thicknesses. These are the tile types to consider when choosing a thinset thickness:

Ceramic Tile

You need a thickness of 3/16 to ⅛ inches for your ceramic tile thinset.  In excess of this will inhibit proper bonding between the substrate and your tile. This excess can also create a mess.

Porcelain Tile

As for the ceramic tile, the thinset you apply to your porcelain tile should be between 3/16 to ⅛ inches.

Glass Tile

Your glass tile mortar thickness should be at least 1/16 inches. This thickness will prevent air spaces forming behind the tile. It shall also help your tile to quickly bond with the substrate.

Marble Tile

The best thinset thickness you should use for your marble tile is 1/2inches.  Likewise, if your marble tiles are thicker than ⅜ inches, you should use a tile mortar thickness of ½ inches.

Granite Tile

If you have a complete granite tile, you should use a  minimum thinset thickness of 3/32 inches. This will help you choose an ideal trowel size for the perfect warpage.

Other Natural Stone Tile

You should have a tile mortar thickness of below ¾ inches for your natural stone tiles. This thickness is suitable for your limestone and travertine tiles.

It Should Be Surface-Specific

Just as different parts of your home call for specific types of tiles, different areas require varying thinset thickness.

This table has the appropriate measurements for your surfaces:

Surface Thinset Thickness
Shower floors 3/16 inches
Walls ¼ inches
Ceilings Less than 3/16 inches
Tub surroundings 12/24 inches

Tile Height Is Also A Factor

Thinset adds to the height of your tile. Thus, if your tyle type or surface needs a tile mortar layer of 3/16 inches, use a tile mortar thickness of 3/8inches. Likewise, use a ⅜ inches square trowel for an even surface.

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When you need a thinset thickness of ⅛ inches, you must use a tile mortar thickness of ¼ inches. A square toothed trowel of ¼ inches would also help facilitate this perfect thickness.

FAQs

Here are some of the most asked questions about thinset, and their answers.

How Do I Calculate Thinset Thickness?

Your thinset layer thickness depends on the type of trowel you use to spread it. For example, when you use a square toothed trowel with even spacing, you’ll get a thinset thickness of half the tooth depth.

using trowel to lay tiles

Hence, if you use a ⅜ inches by ⅜ inches trowel, it will spread your ridges to ⅜ inches apart and ⅜ inches high. The resulting thinset layer will be 3/16 inches thick.

A U-shaped tooth trowel creates a thinset layer that’s one-third as thick as its tooth depth. Hence, if you use a ⅜ inches U-shaped teeth trowel, it will give you thinset that is ⅛ inches thick.

If you are using a trowel with U-shaped teeth, it will create a thinset layer one-third as thick as the tooth depth. So, this thinset trowel with 3/8-inch U-shaped teeth will develop a layer of thinset 1/8-inch thick.

You can also use cardboard to mock up your thinset thickness. Cut off the size of the tile box and place the cardboard under your tiles. This strategy will give you your manufacturer’s recommended thinset thickness.

What Happens If My Thinset Is Too Thick?

Thinset that is too thick can squeeze out from under your tile. When the excess thinset gets into the gaps between your tiles, it inhibits proper grouting.

An appropriate thinset will allow for some variations to help your mortar bond with the substrate.

Conclusion

To calculate thinset thickness, first decide on the kind of thinset mortar you are going to need, based on the characteristics of your tiles and your substrate. Then, consider the surface where it is to be applied, and finally, your personal preference on the height you are looking for.