Oregon R327 versus California CWUIC

People search “Chapter 7A” and “R327” as if they were the same WUI rule. They are not. Oregon lets a city or county that runs a building department adopt ORSC R327 by ordinance. California maps fire hazard areas and, as of 1 January 2026, uses the California Wildland-Urban Interface Code (CWUIC), Title 24 Part 7. Roof class, windows, eave vents, and who must comply all differ. Confirm the adopted code for the lot with the building official.

You are copying a California vent note onto an Oregon drawing, or the reverse. Those books disagree on the floor, not only on the name.

Read dual-pane versus tempered before you copy a California window spec onto an Oregon drawing, or the reverse. Read IBHS does not replace adopted code before you treat a designation as a permit.

Why it matters

The two books disagree on the floor, not only on the name. A California “Chapter 7A listed vents only” note on an Oregon sheet can fail plan review, or it can over-spec tempered glass and a Class A roof when R327 did not ask for them. IBHS Essential still wants Class A. That is a designation. It is not a rewrite of R327. The official stamps code. The carrier reads a checklist.

Embers do not care which book you opened. The permit does.

How it works

Oregon is opt-in. Only a municipality that administers a building inspection program may adopt R327, and only in its entirety. BCD’s local-adoption FAQ is the public mechanics document. It does not rewrite the material sections. Those live in the amendment PDF.

Ashland now has the missing local legal bridge in this corpus. Ordinance 3198 adopts the current ORSC including R327.4 within the City and took effect 1 October 2021. Its local R327.4.1 language and written substantial-compliance waiver remain part of the answer; an Oregon adopter-list bullet alone did not show them.

Grants Pass also has a local legal bridge. Municipal Code Title 9 §9.04.010 adopts the ORSC and Section R327 into the City Building Code, while §9.04.200 says new construction must conform to that code. The City’s current ordinance index dates Ordinance 21-5805 to 2 June 2021. Neither retrieved document supplies an effective date or resolves the wildfire-zone and project trigger for one lot.

California is mapped. You do not wait for your city to “opt in” the way Oregon does. The live book as of 1 January 2026 is CWUIC. People still search Chapter 7A. IWUIC is a model code. Oregon does not use it as a statewide mandate. California’s live book is not IWUIC either.

OSFM listing is a California program and is voluntary for most WUI products. Missing from the handbook is not an automatic ban. Presence is not an automatic permit. Deschutes County will accept handbook products when they are shown on the drawings. That is local practice. See listing is voluntary and show the product on the drawings.

The rules

Two construction books. They are not synonyms. Spec the stricter line if more than one document applies to the same house.

1. Who must use it. Oregon R327 applies only where a city or county that runs a building department has adopted it. Oregon BCD lists adopters. As of 27 August 2026 that page names Ashland, Deschutes County, Grants Pass, and Sisters. Grants Pass is additionally sourced to current Municipal Code §§9.04.010 and 9.04.200 and an ordinance-index date, but not an effective date or parcel trigger. The BCD page omits both Bend and Medford. Current Bend Code separately applies R327 throughout Bend city limits; no current Medford R327 enactment is established here. See the adoption dataset. California CWUIC applies in mapped Fire Hazard Severity Zones and related WUI areas.

2. What the job is. BCD’s local-adoption FAQ says R327 applies to new construction of new buildings governed by the ORSC. Typical additions, alterations, and a roofing or siding swap on an older house are out, unless that dwelling was originally built to R327. Deschutes County says the same for typical additions. Manufactured dwellings follow HUD, not ORSC. Commercial buildings follow the Oregon Structural Specialty Code, not R327. CWUIC is new construction in mapped California areas. Local amendments exist. IBHS and CAL FIRE can still ask for retrofit work that code does not require.

3. Roof. Where R327 is adopted, the floor is a Class B assembly equivalent. Wood shakes and wood shingles are not permitted. CWUIC 504.2 is typically Class A. IBHS Essential wants a Class A covering. Spec Class A if you need the designation. Do not tell the official that R327 requires Class A. See roofing and covering versus assembly.

4. Windows and glazed doors. R327.3.6 lists tempered glass, multilayered glazed panels, glass block, or a 20-minute fire rating. Those are or options. Dual-pane is multilayered as written. You do not need both dual-pane and tempered to meet that floor. Deschutes County names double-pane windows as a commonly used fire-hardening material. Confirm with the building official. CWUIC 504.8 wants multilayered panels with at least one tempered pane, or glass block, a 20-minute rating, or an SFM 12-7A-2 listed window. Dual-pane without a tempered pane is the Oregon mix-up to avoid on a California job. See windows, doors, and dual-pane versus tempered.

5. Vents and the 12-foot number. R327 wants mesh 1/16–1/8 inch on ventilation openings, or vents designed to resist ember and flame. Eave, soffit, and cornice vents are restricted except a manufactured ember- and flame-resistant vent the official accepts, or an opening 12 feet or more above grade. CWUIC still allows mesh or an E2886 / OSFM listed vent. The 12-foot threshold is Oregon detailing. Deschutes County notes there is no 12-foot exception for the underside of elevated decks. Stairs to those decks are a BCD exemption in the county FAQ. Read the FAQ. Do not invent a stair rule. See vents, the 12-foot rule, and mesh versus listed vents.

6. Walls. R327.3.3 lists noncombustible material, ignition-resistant material, heavy timber, log, or an ASTM E2707 tested assembly. Coatings are not on that list. Presenters at the 25 June 2026 Central Oregon seminar said coatings are not accepted. See Findings and siding.

Deschutes County and Sisters made R327 mandatory for new ORSC dwellings and new accessory structures on 1 April 2026. Current local pages establish unincorporated Deschutes and Sisters city limits as the two geographies and name the ordinary additions, repairs, remodels, manufactured dwellings, commercial-code buildings, and small detached accessory structures that are outside the County’s described path. Confirm the parcel and project with the administering building department.

What people mix up

• Treating R327 and CWUIC as the same WUI chapter with different numbers.
• Treating IWUIC as Oregon’s book. It is a model code. Oregon’s path is optional local R327.
• Calling Chapter 7A the live California book. The live book is CWUIC as of 1 January 2026.
• Telling a California client that Oregon’s multilayered (dual-pane) option satisfies CWUIC glazing. California wants at least one tempered pane or another 504.8 path.
• Importing “Chapter 7A listed vents only” onto an Oregon drawing when the official did not ask for that.
• Telling the official that R327 requires a Class A roof. The code floor is Class B equivalent. IBHS Essential is the Class A line.
• Treating Bend seminar attendance as R327 adoption. Seminar is event testimony. Bend adopted R327 by Ordinance NS-2552. BCD’s published list still omits Bend as of verification.
• Treating a gutter, siding, or window swap on an older house as an automatic R327 job. BCD’s FAQ says new construction of new buildings, unless that dwelling was originally built to R327.
• Treating an attached ADU as a new dwelling. BCD’s FAQ says a newly built detached ADU is a new dwelling. An ADU attached to an existing dwelling as an addition is not subject to R327.
• Treating a manufactured home as an ORSC job. HUD is the standard. Many manufacturers offer a wildfire package as an option. That is not R327.
• Assuming every OSFM handbook product is required in Oregon. Listing is voluntary. Deschutes accepts handbook products when they are shown on the drawings.
• Using a coating as an R327 wall path. It is not on the list.

How to check

1. Name the lot. Oregon or California. Incorporated city or unincorporated county.
2. If Oregon, open BCD’s adopter list, then call the local building department. The list is not a map of every tax lot. A city inside an adopting county may still run its own program.
3. If California, name whether the lot is in a mapped fire hazard area. See how to read a CAL FIRE FHSZ map. The live book is CWUIC.
4. Name whether IBHS, an HOA spec, or a carrier extra also applies. Spec the stricter roof, vent, and glass line where more than one document binds the same house.
5. If R327 applies, spec to the amendment PDF. Do not spec from a California 7A checklist.
6. If you use an OSFM handbook product, put the manufacturer, model, and listing program on the drawing. Confirm the live GOVmotus record. Do not invent a listing ID.

County hubs are not built yet. The facts above are labeled Oregon or California so they can live on a national URL.

Limits

This page does not stamp your permit. It does not keep BCD’s adopter list current by itself. Recheck the BCD page. A city ordinance can precede that list. See the adoption dataset. It does not make the house fireproof. It does not replace reading R327 or CWUIC for the lot in front of you. Accessory-structure size and setback rules differ slightly between BCD’s FAQ and a county page. Confirm the job with the building official. FireApproved is not the listing body and not the official.

Related records

• Windows, doors, vents, roofing, eaves, siding
• CWUIC, Chapter 7A, IWUIC, SFM 12-7A-2, OSFM BML
• Dual-pane versus tempered
• IBHS does not replace adopted code
• The 12-foot rule
• When R327 hits an ADU, garage, or shop
• R327 remodels when the answer is no
• Craftsman eaves under R327
• Mesh versus listed vents
• Covering versus assembly
• Show the product on the drawings
• Listing is voluntary
• R327 adoption dataset
• Coatings are not an R327 wall path
• Wood shake is not an R327 roof path
• Manufactured homes are outside R327