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 Data	Properties	ASTM
Weight	7.6 lbs/ft² at 3/4" (19 mm)	C472M
Thickness	3/4" (19mm) (minimum over wood) to 3 1/2" (89mm); 1/2" (13mm) (minimum over concrete)
Compressive Strength	2000 - 3300 psi	C472M
Thermal Performance	K-value of 2.8 Btu/ft²·h·°F; R-value of 0.36 ft²·h·°F/Btu	C177
Fire Hazard Classification	Flamespread index 0; Fuel Contribution 0; Smoke Density 0	E84, E136
Patty Size	8 1/2" (approx. 216mm) plus or minus 1/2" (13mm) in diameter
Sand	1/8" (3mm) or less washed plaster or masonry sand	E11
UL listings	Listed in over 100 1, 2, 3, and 4-hour floor/ceiling assemblies

Technical specification

Unique ref.firm-fill-3310-floor-underlayment
Product familyGypsum Cement Underlayment
Product groupGypsum Concrete Floor Underlayment
TypeObject (single object)
Date of publishing2026-03-02
Edition number1

Links

Product urlhttps://hackerindustries.com/firm-fill-3310.shtml
Installation instructionshttps://hackerindustries.com/pdfs/Firm-Fill-Post-Pour-Instructions.pdf
Technical descriptionhttps://hackerindustries.com/3-part-specs/FF_3310C_Specs.pdf

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