Vented fiber-cement soffit is not by itself an ember-rated eave vent

not-an-ember-rated-vent

Perforated or louvered fiber-cement soffit panels are a cladding product. Where eave ventilation is allowed, R327.3.2 asks for noncombustible corrosion-resistant metal wire mesh between 1/16 and 1/8 inch, a vent designed to resist the intrusion of burning embers and flame, or other approved materials. A perforated cladding panel is none of those three on its own. R327 does not name a test method for that vent; ASTM E2886 is the test the industry uses to demonstrate it, not a path the Oregon text cites. Deschutes County’s R327 page flags soffits under 12 feet as a protected assembly.

As of 2026-08-23. JSON (CC BY 4.0)

Sources

Fire Hardening Requirements (R327) — Deschutes County (official). Accessed 2026-08-29.
The exposed underside of rafter or truss eaves and enclosed Soffits with any portion under 12' from grade - required to be protected.
2023 ORSC Section R327 amendment — Oregon Building Codes Division (official). Accessed 2026-08-29.
R327.3.2. Mesh minimum 1/16 inch and maximum 1/8 inch, or vents designed to resist the intrusion of burning embers and flame, or other approved materials or devices. No test method is named.

Vented fiber-cement soffit is not by itself an ember-rated eave vent. FireApproved. https://fireapproved.com/findings/vented-fiber-cement-soffit-not-ember-vent/. As of 2026-08-23.