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New Test Finds Multifamily Flooring Underlayment Using EXACOR® Panels Installs Faster Than Wet-Laid Gypsum Process

CHARLOTTE, N.C. (September 22, 2022) – In recent third-party time testing by Home Innovation Research Labs, Huber Engineered Woods’ (HEW) EXACOR® Magnesium-Oxide (MgO) panels were found to install 30% faster than a traditional wet-laid gypsum assembly in flooring underlayment applications on a wood-framed flooring system replicating a multifamily-type build.

In the Home Innovation study, commissioned by HEW, installations were measured on a 1,600-square-foot wood-framed truss floor system representative of a typical two-bedroom apartment using materials that would fulfill a commonly specified sound-rated floor system for a multifamily project. The team tested installation times for wet-laid gypsum with sound mat in customarily non-carpeted areas compared to EXACOR panels in a flooring underlayment application. The installation time for an AdvanTech® subflooring assembly using AdvanTech panels, AdvanTech™ subfloor adhesive and proper fastening was utilized for both the wet-laid gypsum and EXACOR underlayment assemblies.

The research team used the Group Timing Technique (GTT) to measure all productive activity by professional installation crews. Installation was continuously monitored and recorded over each application process, from site preparation to clean-up.

The test compared all steps to complete each application, including:

  • For EXACOR underlayment application: installation of AdvanTech® subflooring with AdvanTech™ subfloor adhesive and fastened to joists, followed by EXACOR panel installation finished with a recommended patch coat on panel seams
  • For wet-laid gypsum: installation of AdvanTech® subflooring with AdvanTech™ subfloor adhesive and fastened to joists, pre-pour prep, sound mat installation, perimeter tape and foam sealant application, primer application and gypsum pour

The test revealed the following collected times for each installation:

Underlayment Application


EXACOR Underlayment on Structural Wood Subfloor


Poured Gypsum Underlayment and Sound Mat on Structural Wood Subfloor


“Our team determined through the comparative time study EXACOR installed 30 percent faster in an underlayment application when compared to poured gypsum and sound mat in terms of man-hours” said Ed Hudson, Home Innovation’s Director of Market Research.

EXACOR panels are comprised of a cementitious material reinforced with an internal woven fiber mesh to provide jobsite durability and sound dampening essential for apartment, townhouse or multi-use projects. Because of these performance benefits, EXACOR panels offer an easy-application alternative to labor-intensive wet-laid gypsum underlayment for floor systems in multifamily or other wood-framed commercial projects. Installed like traditional plywood or OSB panels, existing framing crews can install EXACOR panels, which eliminates the need for a specialty gypsum contracting crew on large jobs. This allows builders to reduce scheduling volatility by taking out one subcontractor coordination need.

Replacing wet-laid gypsum with EXACOR panels has helped building teams streamline cycle times by eliminating the curing time, materials and crew required for traditional gypsum-based, water-required underlayment installations, without sacrificing sound and fire protection. In wood-framed construction, managing proper ventilation to prevent mold can also add time-consuming risk-mitigation steps. Unlike wet-laid gypsum alternatives, EXACOR panels do not require water for installation, thus reducing ventilation concerns.

Available in 1/2” (12mm) and 5/8” (16mm) thickness options for underlayment over traditional OSB or plywood subfloors (UL 263 Design Nos. L501, L502, L525, L528 and M500) and in 3/4" (20mm) thickness as a structural subfloor (UL 263 Design Nos. L502, L525, L601 L602 and M500), EXACOR has been shown to help meet or exceed code minimums for STC/IIC ratings for dwelling separations, when tested in these assemblies.

“EXACOR panels are a great substitute for wet-laid gypsum because they help keep cycle times moving with an easy installation familiar to framing crews’ experiences with wood panel installation,” said Kate Land, general manager, MgO products for HEW. “With standard framing tools and no additional curing time or specialty skills required, EXACOR panels can have a big impact for jobs needing to keep schedules moving building-to-building, while achieving assemblies with the fire-resistance and sound protection needed in multifamily projects.”

For more information on EXACOR, visit or view the EXACOR Product Overview.

About Huber Engineered Woods

Building products innovator Huber Engineered Woods LLC has a reputation built on consistent product performance and commitment to people. Fueled by on-the-jobsite insights and building science principles, AdvanTech® subflooring, ZIP System™ building enclosures, and EXACOR™ product solutions have changed the way construction teams build better buildings. Each solution in the product portfolio helps streamline installation while providing dependable performance as critical components of quiet, stiff floors and protective, resilient roof and wall assemblies. Headquartered in Charlotte, NC, Huber Engineered Woods operates facilities in Maine, Georgia, Virginia, Tennessee and Oklahoma and supports customers through a national sales team of over 100 members. Huber Engineered Woods delivers trusted building materials to residential, multifamily and light commercial projects nationwide through a network of lumberyard and distribution partners. Visit to learn more.

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