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FIRM-FILL® Gypsum Concrete | Floor Underlayment
FIRM-FILL® Gypsum Concrete | Floor Underlayment
    Hacker Industries

    FIRM-FILL® Gypsum Concrete | Floor Underlayment

    The original FIRM-FILL® Gypsum Concrete floor underlayment is designed for use in multi-family housing to satisfy acoustical ratings and fire codes. With excellent STC and IIC ratings as well as over 105 UL listings, FIRM-FILL® Gypsum Concrete floor underlayment is an excellent choice for jobs needing compressive strengths up to 2200 psi.

    Recommended For

    • Multi-Family Application / Market: Apartments, condominiums, hotels, motels, dorms, commercial buildings and commercial renovation projects.

    Features & Benefits

    • Flattens subfloors
    • Provides excellent STC (sound transmission) and IIC (impact isolation) ratings
    • Possesses over 105 UL listings
    • Lightweight and crack resistant
    • Easily installed; over 25,000 square feet can be installed per day
    • Quick drying; can be walked on in 90 minutes
    • Expert application; installed only by trained, Licensed Applicators
    • Approvals from ICC-ES and HUD
    • Meets ASTM F2419, Standard Practice for the Installation of Thick Poured Gypsum Concrete Underlayments and the Preparation of the Surface to Receive Resilient Flooring
    Specification
    • Technical DataPropertiesASTM
      Weight7 lbs/ft2 at 3/4" (19 mm)C472M
      Thickness3/4" (19mm) (minimum over wood) to 3 1/2" (89mm)
      Compressive Strength1200 - 2250 psiC472M
      Thermal PerformanceK-value of 2.45 Btu/ft2·h·°F; R-value of 0.41 ft2·h·°F/BtuC177
      Fire Hazard ClassificationFlamespread index 0; Fuel Contribution 0; Smoke Density 0E84,
      E136
      Patty Size8" (203mm) plus or minus 1/2" (13mm) in diameter
      Sand1/8" (3mm) or less washed plaster or masonry sandE11
      UL listingsListed in over 100 1, 2, 3 and 4 hour floor/ceiling assemblies


    Technical specification
    • Unique ref.firm-fill-gypsum-concrete
    • Product familyGypsum Cement Underlayment
    • Product groupGypsum Concrete Floor Underlayment
    • TypeObject (single object)
    • Date of publishing2026-03-02
    • Edition number1
    Links
    Related
    • Designed inUnited States
    • Manufactured inUnited States
    Classification
    • BIMobject CategoryFlooring - Underlay
    • CSI MasterFormat 2014 Code03 54 13
    • CSI MasterFormat 2014 TitleGypsum Cement Underlayment
    • OmniClass Number23-15 17 11 13
    • OmniClass TitleFloor Underlayments

    Region availability

    North America
    Anguilla
    Antigua and Barbuda
    Aruba
    Barbados
    Belize
    Bermuda
    British Virgin Islands
    Canada
    Caribbean Netherlands
    Cayman Islands
    Collectivity of Saint Martin
    Costa Rica
    Cuba
    Curaçao
    Dominica
    Dominican Republic
    El Salvador
    Greenland
    Grenada
    Guadeloupe
    Guatemala
    Haiti
    Honduras
    Jamaica
    Martinique
    Mexico
    Montserrat
    Nicaragua
    Panama
    Puerto Rico
    Saint Kitts and Nevis
    Saint Lucia
    Saint Pierre and Miquelon
    Saint Vincent and the Grenadines
    Saint-Barthélemy
    Sint Maarten
    The Bahamas
    Trinidad and Tobago
    Turks and Caicos Islands
    U.S. Virgin Islands
    United States

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