


EXACOR™ Underlayment
EXACOR™ underlayment panels are specifically engineered to meet the fire-rating[1], sound-rating[1] and dimensional stability requirements of most multifamily and light commercial jobsites. Made of magnesium oxide and an integrated mesh core, EXACOR underlayment panels are fire resistant[2]. In addition, EXACOR underlayment panels can offer a base for floor coverings that can eliminate the need for gypsum underlayment and the jobsite delays that may come with it.
- EXACOR Underlayment Sales Sheet
- EXACOR Underlayment 3-Part Spec (Short Form) Section 06 16 26
- EXACOR Safety Data Sheet
- BXUV L501 Fire-Rated Assembly using EXACOR Underlayment
- BXUV L525 Fire-Rated Assembly using EXACOR Underlayment
- BXUV L602 Fire-Rated Assembly using EXACOR Underlayment and Subflooring
- EXACOR Underlayment Installation Manual
- EXACOR Underlayment Commercial Warranty View All

01 Products

Underlayment Panel, 1/2" × 4' × 8'
Panel Count | 38 |
Fire Resistance | ASTM E119, ANSI/UL 263 |

Underlayment Panel, 1/2" × 4' × 9'
Panel Count | 33 |
Fire Resistant | ASTM E119, ANSI/UL 263 |

Underlayment Panel, 1/2" × 4' × 10'
Panel Count | 32 |
Fire Resistant | ASTM E119, ANSI/UL 263 |
Performance Category | Panel Size | Edge Profile | Fire-Resistant Assemblies | Code Evaluation Report | Approx. Weight Per Panel | Panels Per Unit |
---|---|---|---|---|---|---|
Nominal 1/2" Thickness (12 mm) | Nominal 4' × 8' (1220 mm × 2440 mm) | Straight (Square) Edge | UL L528 | ESR-4750 | 86.4 lbs. | 38 |
Nominal 1/2" Thickness (12 mm) | Nominal 4' × 9' (1220 mm × 2743 mm) | Straight (Square) Edge | UL L528 | ESR-4750 | 97.2 lbs. | 33 |
Nominal 1/2" Thickness (12 mm) | Nominal 4' × 10' (1220 mm × 3048 mm) | Straight (Square) Edge | UL L528 | ESR-4750 | 108.0 lbs. | 32 |
02 What Is MgO
Magnesium oxide (MgO) offers simple strength and streamlined installation for a building panel with exceptional workability.
MgO panels are cementitious panels that are primarily made of inorganic materials reinforced with layers of glass fiber mesh. EXACOR™ MgO panels are manufactured to provide a streamlined solution for strength, fire resistance and sound performance.
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Speed & Ease of Installation
Installs with just a single trade and can eliminate the need for gypsum underlayment.
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Sound Absorption
Can help achieve sound ratings when used as a part of a STC/IIC-tested floor/ceiling assembly.
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Fire Resistance[2]
Provides fire resistance as part of fire-resistance-rated floor/ceiling assemblies
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Dimensional Stability
Withstands exposure to moisture and does not warp, expand, cup or delaminate like other (wood) panels do.
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Inherent Strength
Contains a proprietary layered mesh reinforcement for added structural value.
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Quality Assurance
Manufactured under a quality control program with inspections by ICC-ES and Underwriters Laboratory (UL) to ensure consistent product performance.
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Optimize Material & Labor Costs
High-performing material that may save time and help reduce materials and trades needed to install.
03 How to Install
Installing is fast and simple and doesn’t require additional training.
When used as underlayment, EXACOR MgO panels install in less time, with less steps, and within your crews’ current skill set. No extra tools or skill is needed. If they’ve been installing gypsum underlayment, they’re going to love EXACOR MgO panels.




04 Documents
Resource Library
05 Warranty
Enhanced Experience
If you’re building a multifamily or light commercial project, register your project and complete a preconstruction meeting to access the full range of technical support and warranty benefits for your build, including a transferrable warranty. Review full warranty details and access project registration at the link below.
Explore more products.
06 News & Articles
Behind the Build Blog
Time to Get Started: EXACOR™ MgO Panels Are Available and Ready for Your Job
Where to find EXACOR™ MgO Panels
Read MoreEXACOR™ MgO Panels vs. Gypsum Underlayment in Multifamily Buildings
Explore the differences between EXACOR™ MgO panels and gypsum underlayment for multifamily buildings.
Read MoreHow TDK Construction Saves Time and Money with EXACOR™ MgO Panels: Getting in on the Ground Level
TDK Construction agrees using EXACOR MgO panels equated to real time savings in a recent luxury apartment community project.
Read More