Structural Sheathing for Safer, Stronger Wall Systems

Selecting the right structural sheathing is a critical early decision that affects fire resistance, structural performance, durability, and long-term building resilience. In multi-family, mixed-use, modular, and commercial construction, designers are moving away from traditional wood-based sheathing in favor of stable, non-combustible panels that deliver predictable performance across all climate conditions.

The M4 Structural Wall Panel meets these needs with a certified, non-combustible, ICC-recognized solution purpose-built for structural exterior and interior walls. It provides the strength, stability, and fire-resistance required for today’s code-driven projects.

Why the Choice of Structural Sheathing Matters

Modern assemblies depend on the sheathing layer to achieve:

• Verified 1-hour fire-rated wall assemblies

• Structural and shear performance in lateral-load design

• Resistance to moisture, mold, swelling, and long-term degradation

• Consistency in modular and panelized wall manufacturing

• Reliable performance in open-frame weather conditions

• Compliance with increasingly strict building, fire, and energy codes

A building only performs as well as the system behind the cladding, and structural sheathing is the base of that system.

M4 Structural Wall Panel: Code-Recognized, Non-Combustible Structural Sheathing

The M4 Structural Wall Panel is manufactured from high-purity magnesium-oxysulphate cement reinforced with alkali-resistant fiberglass mesh. It is tested, certified, and designed for structural and fire-rated wall assemblies, functioning as both structural sheathing and a durable non-combustible substrate.

Key Capabilities

• 1-Hour Fire-Rated Wall Assemblies

  ICC-certified structural and shear wall assemblies for both wood and steel framing.

• Non-Combustible (ASTM E136)

  Recognized for use in Types I–V construction requiring non-combustible materials.

• Structural & Shear Capacity

  Supports engineered wall systems without the swelling or variability of wood-based sheathing.

• Weather & Jobsite Durable

  Resistant to moisture, mold, insects, corrosion, and freeze–thaw exposure.

• Healthy & Stable

  No silica, no asbestos, no formaldehyde, and no added chloride.

• Predictable Handling

  Maintains dimensional stability during staging, storage, and installation.

Ideal Applications

• Exterior structural sheathing

• Interior fire partitions and corridor walls

• Modular & panelized wall systems

• Stair towers and vertical shafts

• Multi-family residential & mixed-use projects

Certified to Perform

Fire Testing

• ASTM E119  — 1-hour rated assemblies

• ASTM E84 — Class A surface-burning characteristics

• ASTM E136 — Non-combustible material

Structural & Shear Testing

• ICC-recognized structural and shear wall performance

Durability

• Mold resistance (ASTM D3273)

• Corrosion testing on steel, aluminum & copper (ASTM C665)

• Freeze–thaw resistance and low humidity deflection (per ICC AC386)

Quality Assurance

Manufacturing of our products are independently audited by accredited agencies including UL, ICC and QAI multiple times per year ensuring predictable, code-compliant performance.

Where M4 Structural Sheathing Delivers Value

Builders choose M4 when they need:

• Non-combustible structural sheathing

• Fire-rated wall assemblies without complex layering

• Shear capacity with better stability than OSB or fiber cement

• A dependable substrate in humid, cold, or variable climates

• Materials that can survive open-frame exposure without callbacks

• Performance suited for multi-story, modular, and high-density projects

A Smarter Approach to Structural Sheathing

Choosing structural sheathing is no longer just about structure — it’s about fire protection, moisture resilience, code compliance, and long-term building health.

The M4 Structural Wall Panel gives architects and builders a single, proven solution that meets fire, structural, and durability criteria while simplifying design and installation.

Whether you’re designing multi-story residential, modular structures, or commercial wall systems, M4 provides the reliability demanded by today’s building codes.

Build Stronger Walls with Certified Structural Sheathing

If your next project requires non-combustible structural sheathing, fire-rated wall assemblies, or improved wall durability, our technical team can help you evaluate the right solution for your application.