Subfloor for Type I and II construction

Direct answer: Type I and II are the non-combustible construction types, so the structural floor deck must be a non-combustible material (ASTM E-136) — which rules out plywood and OSB. JARA High Performance Subfloor is a fiber-cement structural panel that is non-combustible per ASTM E-136, ASTM E-84 Class A, and UL R15140 classified for 1-hour and 2-hour fire-rated floor/ceiling assemblies, with IBC 2021 Type I/II recognition and California Building Code Chapter 7A compliance for wildfire zones.

What a Type I/II subfloor must satisfy

Non-combustible material

ASTM E-136 non-combustibility is the defining test for Type I/II elements.

Surface burning

ASTM E-84 Class A (flame spread 0, smoke developed 0).

Fire-rated assembly

UL R15140 classified assemblies (H502, H504, H511, U449, U487) for 1-hour and 2-hour floor/ceiling ratings.

Code recognition

IBC 2021 Type I/II references (§602, §711, §803, Table 601); IAPMO ER-360 evaluation report.

Wildfire (WUI)

California Building Code Chapter 7A + §420 for Wildland-Urban Interface zones.

Where it is specified

Multifamily Type V over a concrete podium, hotels, steel-joist Type I/II commercial floors, and modular construction — assemblies where a combustible plywood deck is not permitted or where the floor/ceiling must carry a fire rating. JARA provides the UL assembly references, ASTM reports, and the IAPMO evaluation report needed for AHJ submittal.