Natural Stone & Large Tile Premium Mortar

Product ID: TDS-309

Premium quality, polymer-modified mortar for natural stone or large format tile 15″ (38cm) or larger on one or more sides. Can be used for clay pavers or other thin or medium bed applications (up to 3/4″ thick). Non-slumping formula minimizes lippage.
Formerly named Marble, Granite & Travertine Premium Mortar

  • Supports large and heavy tile for flat, even floor installations
  • Sag and slip resistant – immediately holds wall tiles in place
  • Exceeds ANSI A118.4 and A118.11

Coverage Chart


Trowel Size Min Coverage Max Coverage
Longest side of tile less than 8" use 1/4" x 1/4" x 1/4" (6 x 6 x 6 mm) Square-Notch 90 sq. ft. (8.4 M²) 100 sq. ft. (9.3 M²)
Longest side of tile 8" to 15" use1/4" x 3/8" x 1/4" (6 x 9.5 x 6 mm) Square-Notch 63 sq. ft. (5.9 M²) 70 sq. ft. (6.5 M²)
Longest side of tile more than 15"+ use 1/2" x 1/2" x 1/2" (13 x 13 x 13 mm) Square-Notch 45 sq. ft. (4.2 M²) 50 sq. ft. (4.6 M²)
Longest side of tile more than 15"+ use 3/4" × 9/16" × 3/8" (19 × 14 × 9.5 mm) U-Notch 36 sq. ft. (3.3 M²) 40 sq. ft. (3.7 M²)

Recommended minimum coverage (80% for dry areas and 95% for wet areas and exteriors). Back buttering may be necessary.

Note that mortar coverage does not include backbuttering tiles. When backbuttering, consider the tile underside pattern and depth to estimate thickness and usage to add to your estimate.

Chart for estimating purposes. Coverage may vary based on installation practices and jobsite conditions. For more sizes, use the material calculator at or contact CUSTOM Technical Services at 800-282-8786.

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