How to Use Modified or Dry Set Mortar

Modified and dry set mortar are commonly used for setting tile.

Modified and dry-set mortars are actually two slightly different types of thin set mortar used in indoor applications. Dry-set mortar is the kind of mortar that you typically think of when you think of mortar. It is comprised of sand, Portland cement, lime and water. Modified mortar, on the other hand, is comprised of the same components, with the addition of a latex additive. This additive increases the strength of the mortar by giving it more elasticity, so that it can more easily adapt to shrinking and expanding of the substrate on which the mortar is applied. While there are differences between the two, they are still applied the same way.

Things You'll Need

• Mixing container
• Mason's trowel
• Water

Instructions

1. Empty the bag of either modified or dry set mortar into the mixing container, being careful not to allow too much dust to rise. If it does, avoid breathing this dust, as it can irritate your lungs.

2. Add water to the mortar mix and fold them together using the trowel. The ideal consistency of either type of mortar is that of peanut butter. Allow the mortar to rest after mixing for approximately 10 minutes prior to using the material.

3. Apply the mortar to the surface that is being finished. If you are tiling, scrape the surface with the toothed edge of the trowel to ensure that you have applied an even coat over the surface.

4. Press the tile into the mortar, lightly tapping the surface to ensure that the tile seats properly into the mortar.

Tips & Warnings

• The primary difference between modified and dry set mortar is that modified can be used in outdoor applications, where dry-set mortar is only recommended for use indoors.

References

• "Stanley Complete Tiling"; Ken Sidey; 2004
• "Tiling Complete"; Michael Schweit; 2008
• Online Tips: Dry Set Vs. Latex Tile Mortars