United States / Build / WoodSyn OptimBoard™ wood-wool cement sheathing

WoodSyn OptimBoard™ wood-wool cement sheathing

Name: WoodSyn OptimBoard™ wood-wool cement sheathing
Brand: WoodSyn, LLC

This is a listed siding assembly. Listing 8170-2435:0001. This site cites OSFM BML. Match the model and orientation.

WoodSyn describes OptimBoard as a noncombustible, Class A wood-wool cement panel. CAL FIRE OSFM listing 8170-2435:0001 covers 2400-by-600-millimetre boards from 1 through 4 inches thick as exterior sheathing in wood-framed walls, installed behind a WUI-approved exterior wall covering.

Kind: listed-assembly. Brand: WoodSyn, LLC. Listing evidence: OSFM WUI handbook 2026-08-25. Page reviewed 2026-08-29. JSON (CC BY 4.0)

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Documented attributes

Each value below points to its field-level manufacturer, official-listing, test-report, or standard-body evidence.

Attribute	Value	Evidence source
Form
Solid surface	Yes	WoodSyn OptimBoard product overview (manufacturer)
Fire
Fire rating	class a	WoodSyn OptimBoard product overview (manufacturer)
Noncombustible	Yes	WoodSyn OptimBoard product overview (manufacturer)

Published requirement matches

These links are generated from the cited attributes above. They do not decide installation or a project result.

Colorado CWRC noncombustible wall · Colorado jurisdictions adopting CWRC in moderate or high mapped wildfire hazard areas
California noncombustible wall · California mapped fire hazard areas
2018 IWUIC Class 1–2 noncombustible wall · Jurisdictions adopting unamended 2018 IWUIC Chapter 5
2021 IWUIC Class 1–2 noncombustible wall · Jurisdictions adopting unamended 2021 IWUIC Chapter 5
IWUIC Class 1–2 noncombustible wall · Jurisdictions adopting unamended 2024 IWUIC Chapter 5
Kittitas IR1 noncombustible wall · Unincorporated Kittitas County IR1 construction
ORSC R327 noncombustible wall · Oregon local jurisdictions that adopted ORSC R327
2006 Utah UWUI Class 1–2 noncombustible wall · Utah local compliance agencies adopting the 2006 Utah Wildland-Urban Interface Code

Program	ID / source	Evidence date	Expires	Status
CAL FIRE BML	8170-2435:0001 · Search BML for 8170-2435:0001	2026-08-25	2027-06-30	listed

Tests and programs cited

OSFM BML · listing-program

Models named on the listing

Model	Application
OptimBoard wood-wool cement board	2400 × 600 mm boards in thicknesses ranging from 1 inch to 4 inches, as exterior sheathing behind a WUI-approved wall covering

Specification notes

The OSFM listing covers OptimBoard as sheathing behind a WUI-approved exterior wall covering, not as the exposed covering. Match panel thickness and dimensions, framing, fasteners, joints, covering, and assembly details to listing 8170-2435:0001 and current WoodSyn instructions.

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Local force

The rule and every matching product for the United States

Requirement constraints (16)

Each table compares this product's documented attributes with one published requirement. The comparison does not change from place to place, so it is printed once.

ORSC R327 noncombustible wall matched
Field	Required	Documented value	State
Noncombustible	Noncombustible = Yes	Yes	matched

IWUIC Class 1–2 noncombustible wall matched
Field	Required	Documented value	State
Noncombustible	Noncombustible = Yes	Yes	matched

IWUIC Class 1 wall-base protection undocumented
Field	Required	Documented value	State
Assembly role	Assembly role = wall base protection	Not documented	undocumented
Height	Height ≥ 6 in	Not documented	undocumented
Noncombustible	Noncombustible = Yes	Yes	matched

California noncombustible wall matched
Field	Required	Documented value	State
Noncombustible	Noncombustible = Yes	Yes	matched

California one-hour exterior wall undocumented
Field	Required	Documented value	State
Fire resistance	Fire resistance ≥ 60 min	Not documented	undocumented

California SFM 12-7A-1 wall undocumented
Field	Required	Documented value	State
Test standard	Test standard = sfm 12 7a 1	Not documented	undocumented

Colorado CWRC noncombustible wall matched
Field	Required	Documented value	State
Noncombustible	Noncombustible = Yes	Yes	matched

Colorado CWRC wall-base protection undocumented
Field	Required	Documented value	State
Assembly role	Assembly role = wall base protection	Not documented	undocumented
Height	Height ≥ 6 in	Not documented	undocumented
Noncombustible	Noncombustible = Yes	Yes	matched

2018 IWUIC Class 1–2 noncombustible wall matched
Field	Required	Documented value	State
Noncombustible	Noncombustible = Yes	Yes	matched

Kittitas IR1 noncombustible wall matched
Field	Required	Documented value	State
Noncombustible	Noncombustible = Yes	Yes	matched

Kittitas IR1 one-hour wall undocumented
Field	Required	Documented value	State
Fire resistance	Fire resistance ≥ 60 min	Not documented	undocumented

Kittitas Table 503.1 N.C. wall undocumented
Field	Required	Documented value	State
Fire resistance	Fire resistance ≥ 60 min	Not documented	undocumented
Noncombustible	Noncombustible = Yes	Yes	matched

2021 IWUIC Class 1–2 noncombustible wall matched
Field	Required	Documented value	State
Noncombustible	Noncombustible = Yes	Yes	matched

2006 Utah UWUI Class 1–2 noncombustible wall matched
Field	Required	Documented value	State
Noncombustible	Noncombustible = Yes	Yes	matched

2006 Utah UWUI Class 1–2 one-hour wall undocumented
Field	Required	Documented value	State
Fire resistance	Fire resistance ≥ 60 min	Not documented	undocumented

2006 Utah UWUI Table 503.1 N.C. wall undocumented
Field	Required	Documented value	State
Fire resistance	Fire resistance ≥ 60 min	Not documented	undocumented
Noncombustible	Noncombustible = Yes	Yes	matched

Sources

OSFM Building Materials Listing (live database) — CAL FIRE OSFM (listing-body). Accessed 2026-08-23.
WoodSyn OptimBoard product overview — WoodSyn, LLC (manufacturer). Accessed 2026-08-25.

WoodSyn OptimBoard™ wood-wool cement sheathing. FireApproved. https://fireapproved.com/materials/woodsyn-llc-optimboardtm/. Last verified 2026-08-29.