All Products

A quiet living space is our business. We supply a full line FIRM-FILL® Sound Control Mats (SCM) and FIRM-FILL® Gypsum Concrete Underlayments (GCU) that meet strict sound and fire attenuation codes. Our FIRM-FILL® SCM are reliable sound control mats color coded to ensure correct installation. Our FIRM-FILL® GCU line offers a variety of options that have shown proven performance over plywood, OSB, corrugated steel deck, concrete or any structurally sound substrate. Knowing which FIRM-FILL® SCM and FIRM-FILL® GCU to choose for your next project is essential. Download and print our Product Guidelines PDF.


FIRM-FILL® Gypsum Concrete

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 100 UL listings, FIRM-FILL® Gypsum Concrete floor underlayment is an excellent choice for jobs needing compressive strengths up to 2200 psi.

FIRM-FILL® 2010+

For use over wood subfloors, FIRM-FILL® 2010+ floor underlayment is the product of choice. It stiffens the subfloor to eliminate squeaks and nail pops and provides a solid floor while remaining safe for the environment. FIRM-FILL® 2010+ floor underlayment creates additional surface hardness and compressive strengths up to 3200 psi.


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.

FIRM-FILL® 3310+

FIRM-FILL® 3310+, a premium poured floor underlayment from Hacker Industries, Inc., delivers best in class performance with compressive strengths from 3000-3900 psi. Ideal over wood or concrete subfloors in multi-family, hospitality, and renovation projects, FIRM-FILL® 3310+ maximizes sound control and creates an enhanced surface for finished floor coverings.

FIRM-FILL® High Strength

FIRM-FILL® High Strength floor underlayment is the economical solution to correct concrete problems. It resurfaces any cracked or damaged concrete to better than new, providing surface hardness from 2500 to over 3800 psi. From feather edge to 3-1/2 inches in thickness, FIRM-FILL® High Strength floor underlayment provides a durable, flat floor for virtually any finished floor covering.


FIRM-FILL® 4010 floor underlayment is designed for thin capping of concrete in new construction or over damaged concrete in renovation projects. FIRM-FILL® 4010 floor underlayment’s high strength and superior bonding characteristics will provide concrete floors with new life and exceptional surface hardness, offering compressive strengths ranging from 4000 to 5200 psi.

TRUE-SCREED® Cementitious Leveling Underlayment (CLU)

TRUE-SCREED® Cementitious Leveling Underlayment (CLU) is a Portland cement-based underlayment that is specifically designed for projects with deep-fill requirements that need to stay on budget. TRUE-SCREED® CLU provides a cost-effective method to transform cracked, uneven concrete floors into a smooth, strong surface for finished floor coverings. The product also offers exceptional surface hardness and quick drying time, keeping construction projects on schedule.

GYP-SPAN® Radiant

GYP-SPAN® Radiant is a gypsum concrete floor underlayment designed specifically for use over radiant heating systems. It encases the tubes or cables without air bubbles, creating a superior thermal mass that provides uniform heat transfer. GYP-SPAN® Radiant floor underlayment is the energy efficient and cost-effective way to create a smooth, flat, evenly heated floor surface for the attachment of virtually any finished floor covering.

FIRM-FILL® CMD (Corrugated Metal Decking)

Designed for use in multi-family, commercial and institutional buildings with light-gauge steel framing and a corrugated steel deck, FIRM-FILL® CMD is a lightweight, high-strength gypsum concrete floor underlayment. Installed at 1″ above the top of the flutes, FIRM-FILL® CMD reduces deadloads and thickness, significantly lowering costs.

FIRM-FILL® SCM-125 (Sound Control Mat)

FIRM-FILL® SCM-125, a 1/8″ (3 mm) sound control mat, is engineered to limit impact sound transmission in multi-family construction. Ideal for when the gypsum concrete pour is not a standard thickness, FIRM-FILL® SCM-125 is topped with a minimum of 3/4″ (19mm) of a FIRM-FILL® Brand Gypsum Concrete to create an effective low profile sound control system.

FIRM-FILL® SCM-250 (Sound Control Mat)

FIRM-FILL® SCM-250 (Sound Control Mat) is a 1/4″ (6 mm), random filament, corrugated, “U” groove core sound control mat designed to limit impact noise between floors. Used in conjunction with a 1″ FIRM-FILL® Brand Gypsum Concrete topping.

FIRM-FILL® SCM-400 (Sound Control Mat)

FIRM-FILL® SCM-400, is a 3/8″ (10mm) sound control mat, is efficiently engineered to provide additional impact noise control when a thicker sound mat is specified. It is a cost-effective way to address Impact Insulation Class (IIC) concerns. Ideal for when the gypsum concrete pour is not a standard thickness.

FIRM-FILL® SCM-750 (Sound Control Mat)

FIRM-FILL® SCM-750, is a 3/4″ (19mm) sound mat, that helps create sound resistant floors with the high IIC and STC level required by IBC 2009. It is a cost-effective way to address higher IIC requirements.

EnkaSonic® 250 Plus

Enkasonic® 250 plus is a 1/4” (8 mm) entangled net acoustical sound control mat with an additional layer of fabric for increased sound muffling. Its thin profile helps maximizes sound control in tight construction projects.

EnkaSonic® 400 Plus

Enkasonic® 400 Plus is a 3/8” (12 mm) entangled net sound control mat with an additional layer of fabric for increased sound control. Increases the IIC performance of the floor/ceiling assembly by up to 18 points over wood and up to 25 points over concrete construction.

EnkaSonic® 750 Plus

Enkasonic® 750 Plus is a 3/4” (20 mm) entangled net sound control mat with an additional layer of fabric for increased sound control. It is our thickest sound mat and offers the highest level of sound resistance in its class.

Hacker Sound Mat I

Thickness 0.08 (2mm). Hacker Sound Mat I is a flat resilient rubber sound control underlayment used directly under all floor finishes, yielding exceptional results even under hard surface flooring and over concrete and wood joist construction.

Hacker Sound Mat II

Hacker Industries, Inc. continues to provide solutions for maximizing sound control in multi-family projects, commercial buildings, and custom homes with the introduction of Hacker Sound Mat II. This innovative sound mat is composed of 92 percent recycled rubber and is designed to provide a quieter environment and meet the most demanding project specifications.

Hacker Floor Primer

Hacker Floor Primer is a white, liquid ethylene-vinyl co-polymer that is designed to enhance the bond between a FIRM-FILL® Brand Gypsum Concrete and the existing structural substrate (wood, concrete, or existing floor coverings). Hacker Floor Primer is packaged in a concentrated formula that must be diluted with potable water before use. Contact Hacker Industries, Inc. for mixing instructions.

Hacker Floor Sealer

Hacker Floor Sealer is a clear, water-based, vinyl acrylic co-polymer sealer that is recommended over Hacker floor underlayments (depending on the specified finished floor covering adhesive).

Hacker TopCoat® SP (Surface Prep)

Hacker TopCoat® SP is an acrylic based, film-forming surface preparation agent designed to meet ASTM F2419-05 compliance requirements for use on Thick Poured Gypsum Concrete Underlayments specified to receive resilient floor coverings. When used in conjunction with Hacker floor underlayments, Hacker TopCoat® SP provides optimal surface bonding conditions for most floor covering adhesive products.

Hacker Reinforcement

Hacker Reinforcement is a reinforcement product used in conjunction with Firm-Fill® SCM Sound Control Mats and Firm-Fill® Gypsum Concrete Underlayments for crack suppression and to reduce the gypsum underlayment pour depth. Potential movement of subfloors have usually been addressed by installing metal lath prior to pouring the underlayment. Typically, reinforcement for gypsum concrete was handled by galvanized metal lath, which could be difficult to install and costly.