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Wildfire-Resistant Siding and Decks in Central Oregon: Deschutes County's R327 Guide
Living in Central Oregon—surrounded by ponderosa pines, juniper, and high desert brush—means building with wildfire resilience in mind. Across Bend, Redmond, Sisters, Sunriver, Tumalo, and La Pine, homeowners are upgrading aging wood siding and weathered decks to ignition-resistant materials that protect against wind-driven embers, boost curb appeal, and help protect homeowner insurance eligibility.
Additionally, if you are building a new dwelling or new accessory structure in unincorporated Deschutes County or within the City of Sisters, wildfire-resistant materials are mandatory under Oregon Residential Specialty Code (ORSC) Section R327 beginning April 1, 2026.
What Changed on April 1, 2026? Deschutes County & Sisters R327 Rules
According to Deschutes County Fire Hardening Requirements (R327), Deschutes County and the City of Sisters adopted local ordinances making ORSC Section R327 (Wildfire Hazard Mitigation / Fire Hardening) mandatory starting April 1, 2026:
Where Mandatory: All areas of unincorporated Deschutes County and within the city limits of the City of Sisters.
What Structures It Applies To: All newly constructed dwellings and all newly constructed accessory structures governed by the ORSC.
Code Exemptions: Remodels or additions to existing homes, partial repairs, manufactured dwellings (HUD standard), and non-habitable detached accessory structures under 400 sq. ft. and not exceeding 15 feet in roof height.
Why Existing Homeowners Still Upgrade to R327 Standards: Even when a re-side or deck replacement in Bend or rural Deschutes County is exempt from mandatory code enforcement, choosing R327-compliant fiber cement siding and ignition-resistant decking provides critical ember protection and helps satisfy insurance underwriting inspections.
Fire-Resistant Siding Requirements (ORSC R327 Exterior Wall Coverings)
Per the Oregon BCD Wildfire Home Hardening Guide and Deschutes County's R327 rules, exterior wall coverings from the top of the foundation to the roof must be one of four compliant assemblies:
Noncombustible Siding (James Hardie® Fiber Cement, Metal, Masonry, Stucco): Cementitious siding (such as HardiePlank® lap siding and HardiePanel® board-and-batten) is explicitly cited by Deschutes County as a premier compliant material. It resists direct flame, flying embers, woodpeckers, rot, and High Desert freeze-thaw cycles.
Ignition-Resistant Material: Materials tested in accordance with ASTM E84 or UL 723, or vetted in the CalFire WUI Building Materials Listing Handbook accepted by Deschutes County Building Safety.
Heavy Timber Assembly: Post-and-beam systems with main framing members measuring at least 8 inches by 8 inches.
Log Wall Assembly: Qualifying solid log wall construction.
Wildfire-Resistant Decks, Porches & Balconies (ORSC R327.4.7)
Under ORSC R327.4.7 and Deschutes County's Fire Hardening Clarifications, walking surfaces of decks, porches, and balconies located more than 30 inches and less than 12 feet above grade must use:
Noncombustible Decking: Stone, pavers, concrete, aluminum, or mineral-based decking.
Ignition-Resistant / Class B Composite or PVC Decking: Deck boards complying with ASTM E2632 / ASTM E2726 or ASTM E84 Class B flame-spread standards (and listed in the CalFire WUI Handbook) when paired with compliant house siding.
Exterior Fire-Retardant-Treated Wood: Pressure-impregnated exterior fire-retardant wood.
Small Deck Exception: Decks, porches, and balconies not exceeding 200 square feet in area constructed with nominal 2-inch lumber.
Underfloor Protection: Elevated structures must have underfloor areas enclosed to grade or protected on the underside (heavy timber columns and beams are exempt).
Complete Exterior Hardening: Vents, Eaves, Gutters & the 5-Foot Zone
Ember-Resistant Vents (R327.3.2): Attic, eave, soffit, and crawlspace vents less than 12 feet above grade must be ASTM E2886 certified flame/ember-resistant vents or covered with 1/16-inch to 1/8-inch noncombustible corrosion-resistant metal wire mesh (replacing older 1/4-inch mesh).
Enclosed Eaves & Soffits (R327.3.4.1): Undersides of eaves and soffits less than 12 feet above grade are protected with noncombustible fiber cement soffits, ignition-resistant material, or 5/8-inch Type X exterior gypsum sheathing.
Noncombustible Gutters & Guards (R327.3.1): Metal gutters and downspouts with gutter guards to prevent pine needle accumulation.
Double-Pane Glazing & the 0–5 Foot Noncombustible Zone: Pair double-pane tempered windows with 6 inches of exposed concrete foundation below siding and gravel, stone, or pavers (never bark mulch or woodpiles) within 5 feet of walls and decks.
Upgrade Your Home with Fire-Hardened Siding & Decking
Whether you are building a new R327-compliant structure in Deschutes County or Sisters, or re-siding and rebuilding your deck in Bend, Redmond, Sunriver, Tumalo, or La Pine, call Foster Builders at (503) 809-1197 or email hello@foster-builds.com for a free estimate.
Foster Builders, a dba of Fosters Framing And Remodeling LLC · CCB #214990 – Licensed, Bonded & Insured
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