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

External Resources

Sweets ProductTAG

CAD Details

Product Resources

Key: Word   PDF   Web Page
Product Submittal
3-Part Specifications
Project References
Drying Conditions Flyer
Post-Pour Instructions
Guidelines for Finished Floor Coverings

Featured Application

Dunn Loring Metro Apartments, Fairfax County, Virginia
Collings Teen Center, West Sacramento, CA
The Grande at Riverdale – Morris County, NJ
Post Lake at Baldwin Park – Orlando, FL
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 2.8Btu/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 Listing Listed in over 100 1, 2, 3 and 4 hour floor/ceiling assemblies