Tile Thinset Mortar: The Major Differences

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January 26, 2017

The most common adhesive for setting tiles is thinset mortar.

This is mortar designed to be applied in a layer no more than 3⁄16 of an inch thick.

Most of these come in white or gray.  If you use a dark-colored grout, choose a gray mortar; choose white if your grout will be a light color.  Achieving a white color requires modifications in the manufacturing process, which is why white costs more than gray.

Not all thinsets are the same.  You choose one based on the location of the surface to be tiled and the nature of the substrate.  When deciding on a thinset to use, the best practice is to look for the American National Standards Institute’s (ANSI) approval for each product.

Most manufacturers offer a range of products that differ in grade, curing time, composition and price.

Here they are…

A118.1:  These mortars contain only portland cement, sand and a water-retention compound.

After being mixed with water, they can be used on basic tile jobs including concrete, drywall, or cement backerboard.

These thinset mortars are called non-modified.

A118.4:  These thinsets must include a latex polymer.  You can buy a mortar including this polymer or you can buy a non-modified mortar and stir in a liquid latex additive in place of the water.

The latex allows a small amount of movement in the substrate.  Mortars that include it are ideal in exterior locations, in wet areas, in high-traffic areas and over vinyl flooring.  These modified thinset mortars also meet A118.1.
or unmodified.

A118.11:  These are mortars with the ability to adhere tiles to exterior-grade plywood as well as A118.1 and A118.4.  You can either buy a thinset that meets this standard or you can buy a non-modified thinset and mix in a latex additive.

Feel free to stop into Builder Supply Outlet or the Edge Showroom with any home improvement questions you may have regarding thinset, tile or anything else.  Or call us anytime at 1-708-343-3900.  You can also make an appointment to meet with one of our designers at no charge by clicking here.