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FIRM-FILL® 3310 | Floor Underlayment
FIRM-FILL® 3310 | Floor Underlayment
FIRM-FILL® 3310 | Floor Underlayment
FIRM-FILL® 3310 | Floor Underlayment
FIRM-FILL® 3310 | Floor Underlayment

    FIRM-FILL® 3310 | Floor Underlayment

    An innovative product that elevates gypsum concretes to an unprecedented level of unyielding performance. FIRM-FILL® 3310 floor underlayment's fast-setting surface rapidly eliminates water allowing for accelerated drying time and unparalleled levels of strength and finish over wood and concrete subfloors in new construction and renovation projects.

    Recommended For

    • Multi-Family Application / Market: Multi-family, custom homes, commercial buildings, hotels & motels, & renovation projects.

    Features & Benefits

    • Premium strength, smooth surface over wood and concrete subfloors
    • Eliminates water rapidly for accelerated drying time
    • FIRM-FILL® 3310 floor underlayment can be poured before or after drywall
    • Exceptional compressive strengths from 2000 to 3300 psi
    • Delivers fire resistance and improved sound performance
    • FIRM-FILL® 3310 floor underlayment creates a smooth, crack-resistant surface
    • Expert application; installed only by trained, Licensed Applicators
    • 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
      Weight7.6 lbs/ft2 at 3/4" (19 mm)C472M
      Thickness3/4" (19mm) (minimum over wood) to 3 1/2" (89mm); 1/2" (13mm) (minimum over concrete)
      Compressive Strength2000 - 3300 psiC472M
      Thermal PerformanceK-value of 2.8 Btu/ft2·h·°F; R-value of 0.36 ft2·h·°F/BtuC177
      Fire Hazard ClassificationFlamespread index 0; Fuel Contribution 0; Smoke Density 0E84,
      E136
      Patty Size8 1/2" (approx. 216mm) 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-3310
    • Product familyGypsum Cement Underlayment
    • Product groupGypsum Concrete Floor Underlayment
    • TypeObject (single object)
    • Date of publishing2026-03-02
    • Edition number1
    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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