PROFLEX® PS 42L is a polymer modified dry set mortar composed of lightweight aggregates, sand, cement, dry resins and other proprietary chemicals used to adhere virtually all types of tile, especially large tile units, marble, and granite to acceptable surfaces. Due to its light-weight and flexible properties, PS 42L installations provide higher resistance to cracking than normal mortars. PS 42L is especially formulated to hold large units in place on vertical surfaces. PS 42L also reduces unevenness caused by setting of the tile when used on horizontal surfaces.


  • ANSI A118.4, ANSI 118.11, ANSI A118.15 compliant
  • Large format tile up to 7 lbs. per sq. ft. installations
  • Lightweight formula


For installation of: Ceramic tile, Pavers, Quarry tile, Porcelain tile, Clay bodied tile, High bottom lugged tile, Marble, Granite, Mosaic, large format tiles, Vertical tile installations up to 7 lbs. per sq. ft.

For installation over: Tile backer board, Plumb and true masonry, Properly cured and finished concrete, Gypsum plaster, gypsum block or gypsum board (dry areas – walls only,) Cured portland cement mortar, exterior grade plywood, plastic laminates, masonry surfaces.


Shear Strength 7 days (psi)28 days (psi)
Quarry Tile250-300500-525
Mosaic Tile250-300400-450
Glazed Wall Tile 350-400450-500
Quarry Tile to Plywood175-200200-250
Compressive Strength4000-45006000-6500
Adjustability15 minutes
Open Time60 minutes
Final Set6-8 hours


Recommended Trowel Sizes

1/2” x 1/2” x 1/2” square notch trowel 40-50 sq. ft., 1/4” x 3/8” x 1/4” square notch trowel 70-80 sq. ft.

Suitable Surfaces

Backer Boards, Plumb and True Masonry, Cured and Finished Concrete, Gypsum Wallboard (dry areas only), Cured Portland Cement, Exterior Grade Plywood, Plastic Laminate, Masonry Surfaces, Proflex Membranes and Underlayments (see warranties)