CustomBlend® LHT Large & Heavy Tile Mortar

Product ID: TDS-455

CustomBlend LHT Large and Heavy Tile Mortar offers a non-sag and non-slump solution for most interior and exterior, wall and floor applications. This polymer modified mortar can be applied ¾” (19mm) thick on horizontal surfaces and can be used for large format porcelain, ceramic and natural stone tile. CustomBlend LHT meets ANSI A118.4HT and A118.11.

  • For most standard floor and wall installations
  • Supports large and heavy tile for flat, even installations
  • For use with in-floor heating systems

Coverage Chart


Trowel Size Min Coverage Max Coverage
Longest side of tile 8" to 15" use 1/4" x 1/4" x 1/4" (6 x 6 x 6 mm) Square-Notch 75 ft² (6.9 M²) 86 ft² (7.99 M²)
Longest side of tile 8" to 15" use 1/4" x 3/8" x 1/4" (6 x 9.5 x 6 mm) Square-Notch 53 ft² (4.9 M²) 62 ft² (5.76 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 37 ft² (3.4 M²) 43 ft² (3.99 M²)
Longest side of tile more than 15"+ use 3/4" × 9/16" × 3/8" (19 × 14 × 9.5 mm) U-Notch 30 ft² (2.8 M²) 33 ft² (3.1 M²)

Recommended minimum coverage (80% for dry areas and 95% for wet areas and exteriors). Flat back-troweling (formerly backbuttering) may be necessary.

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.

Note that mortar coverage does not include flat back-troweling and/or notch back-troweling tiles. When back troweling, consider the tile underside pattern and depth to estimate thickness and usage to add to your estimate. The National Tile Contractors Association / Reference Manual has additional details regarding flat back troweling  See Flat & Notch Back-troweling at