A-81 Underlayment

Our most popular floor underlayment system for patching, smoothing, and resurfacing.

Dex-O-Tex A-81 Underlayment is our most popular underlayment system for preparing irregular floor surfaces for a finished application. Its synthetic copolymer cementitious formulation acts as an ideal patching, smoothing, and resurfacing material beneath any kind of flooring.

A-81 is highly flexible and suitable for both interior or exterior surfaces, including those exposed to freeze-thaw conditions or constant water spillage. It can be applied to any thickness from near featheredge upwards and dries to a charcoal gray color. Natural, cement-gray color is also available on request.

Our pre-packaged formula makes A-81 convenient to unit and easy to mix. It’s also fully VOC compliant with no organic solvents, is non-toxic, and has only a slight odor during placement and cure. This fast-setting system supports foot traffic in 6-8 hours and vehicle traffic after 18-24 hours.


  • Superior adhesion
  • Low permeability, yet breathable
  • Suitable for interior and exterior use
  • Fast setting
  • Excellent freeze-thaw resistance
  • Similar expansion-contraction as concrete
  • Installed only by professional, factory-trained Dex-O-Tex contractors

Please see product safety data sheets.

A-81 Underlayment System Options

A-81 Underlayment

Most widely used Dex-O-Tex underlayment

  • Trowel applied
  • Suitable for application under floors of all types
  • Installed from featheredge to multi-inch thickness
  • Suitable for pitching, patching or filling voids (used widely for creating slope for drainage)
  • Can be left exposed as an industrial finished floor

A-81 SQ Underlayment

Squeegee-applied underlayment for rough or porous substrates

  • Squeegee applied
  • Average application thickness ranges from featheredge to 3/8” (9.53mm)
  • Designed for use as a smoothing or filling compound over rough or porous substrates

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