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It's Not the Cost of the Board.
It's the Cost of the Build.

The cheapest panel rarely makes the cheapest assembly. The real cost of a two-hour fire-rated floor/ceiling assembly lives in places the panel price doesn't show: labor, schedule, additional materials, jobsite coordination, and structural weight. UL Design No. H531 was developed to take cost and time out of the build, not just the board.

Performance Without Compromise

 

"The schedule savings are substantial. By eliminating concrete decking, and the shoring and curing that come with it, the impact on the build is significant." 

Stanley K. Adwell,
 President & Co-Founder, Intellisteel 

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Boards Masked

Five components.Two-hour rating.
No wet trades.

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five_component-updated

 "With these materials, you're going from roughly 50 pounds per square foot down to 13 pounds per square foot for a floor and ceiling system. When you multiply that across three or four floors, you're significantly minimizing project costs by eliminating the added weight, complexity, and labor associated with heavier assemblies." 

Tim Liescheidt,
Managing Member, AdvanT Steel 

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What a two-hour rating
costs elsewhere

Most fire-rated floor/ceiling assemblies in market require additional layers, heavier
steel, brand-specific gypsum, or wet-applied toppings to reach a two-hour rating.
UL H531 simplifies the recipe. And the budget. 

 Click any competitor column for an assembly breakdown ↓ 

Assembly
Feature 		MAXTERRA®H531 UL DesignH515 UL DesignG575 UL DesignH509 UL DesignH514
Ceiling Gypsum 1 layer, ULIX or Type C 1–2 layers, Type ULIX 2 layers, Type FSW-C 2 layers, Type C 1 layer, Type C (National Gypsum only)
Additional Floor Topping None Varies by assembly None None None
Sound Mat in Assembly None Specified in some None None None
Truss Steel Gauge 20 ga 20 ga 16 ga 16 ga 16 ga
Insulation Any qualifying batt Any qualifying batt Any qualifying batt Any qualifying batt R-13, 0.92 density (restricted)
Blocking Required None (tongue & groove) None Required* Specified in some None
Material Cost Premium
per sq ft, vs H531 		BASELINE
$5.20
PER SQ FT 		+$3.49
up to / sq ft 		+$7.02
/ sq ft 		+$4.27
/ sq ft 		+$2.14
/ sq ft

Cost figures reflect assembly materials only. The cost of the subfloor panel itself is not included.

*Blocking note:

UL Design No. G575 was tested with no panel-edge blocking. The listed subfloor panel uses a shiplap edge profile. Where structural panels do not have approved tongue-and-groove joints, Table 2304.8(3) of the 2024 International Building Code requires panel edges to be supported with blocking unless an approved exception applies. Final edge-support requirements should be verified by the project design professional and authority having jurisdiction

Cost comparison methodology and disclaimer:

Estimates are based on reviewed UL assembly configurations, RSMeans data, and third-party supplier or installer quotes available at the time of analysis. References to other UL designs are for assembly-level comparison only and do not evaluate, criticize, or imply that any third-party product is defective, unsuitable, noncompliant, inferior, or endorsed by NEXGEN. Costs are informational only and are not bids, guarantees, or project-specific estimates. Actual costs and requirements may vary; users should verify pricing, code compliance, assembly requirements, and suitability with their design professional, contractor, supplier, and authority having jurisdiction.

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One UL listing.
Three different conversations.

Built for multifamily, hospitality, assisted living, student
housing, data centers, and commercial construction.

FOR ARCHITECTS & ENGINEERS

A clean line in the spec.

Architects need tested, code-compliant assemblies that simplify design in a market squeezed by labor shortages and rising trade costs. Write UL Design No. H531 directly into the documents, and you get a single solution that addresses fire, sound, and moisture requirements without substitution logic or equivalency arguments.

 

FOR BUILDERS & GCS

Finish faster. Get paid sooner.

With 77% of GCs reporting difficulty filling skilled trade jobs, labor savings matter more than ever. H531 cuts wet trades, reduces subcontractor coordination, and uses a lighter 20-gauge steel path, resulting in faster schedules and a lower risk of overruns.

  

FOR DEVELOPERS & OWNERS

Less carry. Higher returns.

Higher interest rates and insurance premiums have made carrying costs a bigger line item than ever. H531 delivers faster installs, fewer trades, and lower rework risk, all of which improve project economics directly by helping you lease, sell, or open sooner.

"Why do we use 3/4" tongue-and-groove MAXTERRA® Structural MgO Panels with Cold-Formed Steel? Simple, it's instant, carries a 2-hour fire rating, and lets us move fast without sacrificing performance. This is how we keep multiple trades moving at once."

Jason Schaller,
Founder, Vitruvian Housing

H531 isn't a one-off. It's the next entry on the list.  

MAXTERRA® holds the most comprehensive third-party certification portfolio of any MgO panel in the North American market. Each listing represents a real test in a real assembly, not a marketing claim. 

UL H531

Two-hour fire-rated floor/ceiling assembly 

The new dedicated UL listing built around a single layer of MAXTERRA® MgO Structural Subfloor, a single layer ULIX or Type C, on 20-gauge cold-formed steel framing. No poured topping, no sound mat, no additional blocking required for the listed rating. 

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Two-hour fire-rated
ICC-ES ESR-5194

Structural performance  

Code-recognized structural evaluation, including approval for cold-formed steel floor assemblies. 

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ESR-5194
ICC-ES ESL-1645

Acoustical performance  

First MgO panel certified for both wood and CFS framing acoustical performance. 

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FLYER-2403 2 (2)
ENVIRONMENTAL PRODUCT DECLARATION

Verified EPD  

The only MgO panel with a verified Environmental Product Declaration for the North American market. 

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Verified-EPD

Frequently Asked
Questions

Are MAXTERRA® structural floor panels the same as cement board?

MAXTERRA® structural floor panels are advanced magnesium oxide (MgO) panels engineered for high-performance floor and floor/ceiling assemblies. As part of the most highly certified MgO panel system in the North American market, MAXTERRA® uses magnesium oxysulfate chemistry and is supported by extensive third-party testing, including ICC-ES evaluation and UL fire-rated assemblies. The result is a structural panel solution designed to deliver fire resistance, moisture resistance, and installation efficiency without relying on traditional Portland cement-based systems. 

Can I specify H531 directly, or does MAXTERRA need to be substituted into another UL listing?

H531 is a dedicated UL-listed assembly built around MAXTERRA® MgO Non-Combustible Single Layer Structural Floor Panels. Architects and engineers can write UL Design No. H531 directly into specification documents without substitution arguments or equivalency logic.

What if my project needs sound attenuation between floors?

UL H531 does not require a sound mat to achieve its two-hour fire-resistance rating, but a sound mat may be added to enhance the acoustic performance of the assembly. The MAXTERRA® panel itself contributes meaningfully to the assembly's acoustic performance, and our ICC-ES ESL-1645 acoustical certification documents the tested STC and IIC ratings for MAXTERRA in both wood and cold-formed steel framing configurations.

If your project has additional acoustic requirements beyond what the assembly delivers on its own, sound mats and other underlayments remain fully compatible with H531. Reach out to our engineering team for project-specific acoustic guidance.

Does H531 require a specific brand of cold-formed steel framing?

The H531 assembly was tested in partnership with AdvanT Steel and is also compatible with FrameCad CFS truss systems. The listing covers cold-formed steel framing meeting the specified gauge, depth, and spacing. Refer to the official UL listing on UL Product iQ for full framing requirements and component alternates.

What building codes and construction types recognize UL H531?

UL Design No. H531 is a UL-listed fire-resistance design that meets fire-rating requirements under the International Building Code (IBC) and locally adopted code variants where UL fire-resistance designs are accepted. The assembly uses non-combustible primary components, including the MAXTERRA® MgO structural subfloor, cold-formed steel framing, resilient channels, and Type ULIX or Type C gypsum ceiling board, with listed glass fiber batt insulation as part of the tested fire-resistance assembly. That combination makes it ideal for IBC Type I, II, III, and V construction wherever a two-hour fire-rated floor/ceiling assembly is required. Refer to the official UL listing on UL Product iQ for the full design specifications.

How do I specify, build a submittal, or estimate cost for H531?

You have three paths. Talk to a NEXGEN engineer for project-specific specification support. Build your own submittal package to generate custom documentation on demand.

Build Faster. Build Safer.
Build Smarter.

Three ways to put UL H531 to work on your project. Talk it through with our engineering team, build your own submittal package, or run the numbers in the Skip-The-Gyp™ calculator.   

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