FireApproved

United States / Build / Fire-resistant siding

Fire-resistant siding

Program and model No adopted WUI code we can source here. IBHS Wildfire Prepared asks for the inspection measures, and the 2024 IWUIC model says the same floor.

National floor. A ZIP opens the same question at a place where a sourced instrument exists.

Fire-resistant siding is a wall covering that is noncombustible under ASTM E136 or ignition-resistant under a named ignition test, or a wall assembly tested to a direct-flame exposure. Where Oregon R327 is adopted, the wall list is noncombustible, ignition-resistant, heavy timber, log, or an ASTM E2707-tested assembly, with 5/8 inch Type X gypsum behind the cladding as a named exception; coatings are not on the list. California's OSFM category 8140 lists siding by model, most tested to SFM 12-7A-1 and some rated noncombustible under ASTM E136. Fiber cement, stucco, brick and metal are the usual families, but the listing for the model decides, not the family.

What the sourced rules ask for

For national siding, the national siding requirement is 2018 IWUIC Class 1–2 noncombustible wall. On national siding, it is shown as model code. Read the national siding rule, then compare 11 matched national siding products.

Review 19 national siding place answers before choosing among national siding records. The national siding links keep the rule, products, and place differences together.

Find what applies near you

Enter a ZIP before browsing the complete evidence. Matching, inherited, and place-neutral records will move first; other places and unmapped application rows will fold into expandable groups. Nothing is removed. All 3 state rule sections remain available.

The rule

Model code “Approved noncombustible materials.”

2018 IWUIC Class 1–2 noncombustible wall. The unamended 2018 IWUIC includes approved noncombustible material as an exterior-wall path in Class 1 and Class 2 construction.

Products matching the model-code floor

Model code Product matches below are limited to siding and trace to the named requirement.

Additional products matching the voluntary program

Voluntary program Product matches below are limited to siding and trace to the named requirement.

No sourced siding product in this directory yet matches the voluntary program.

Questions

What siding is most fire-resistant?

The codes set a floor rather than a ranking. A noncombustible covering under ASTM E136 (stucco, brick, metal, and the fiber-cement models whose listing carries that rating) meets every book on this site; ignition-resistant material and tested assemblies meet Oregon R327 and California CWUIC as named paths. Read the listing for the model.

Is Hardie siding fireproof?

No siding is fireproof. James Hardie fiber-cement products appear in OSFM category 8140 as named models; each listing says whether that model carries an ASTM E136 noncombustible rating or an SFM 12-7A-1 result. The rating belongs to the listed model, not the brand.

Is Hardie Board 1 hour fire rated?

A one-hour rating is an ASTM E119 result for a wall assembly, a different test from the wildfire exposure tests. Oregon R327 accepts the exterior side of a one-hour fire-resistance-rated wall as one path; that rating belongs to the tested wall, not to a board.

Is fiber-cement automatically noncombustible?

No. Fiber-cement is a product family. Some OSFM 8140 listings name ASTM E136 and a noncombustible rating. Others list a model without that rating. Oregon R327 can also be met with ignition-resistant material or with 5/8 inch Type X gypsum behind the cladding. Read the listing and the adopted code.

Can a fire coating on wood siding meet Oregon R327?

The R327 wall list is noncombustible, ignition-resistant, heavy timber, log, or a tested assembly, with named gypsum exceptions. Coatings are not on that list. Presenters at the 25 June 2026 Central Oregon seminar stated coatings are not accepted to meet R327. Confirm with the building official.

Do I need an OSFM listed siding in Oregon?

OSFM listing is a California program and is voluntary for most WUI products. Deschutes County says it will accept products from the OSFM WUI handbook when those products are shown on the drawings. That is local practice. Confirm with the building official.

Is a Hardie soffit panel the same as Hardie wall siding?

No. OSFM category 8140 is exterior wall siding and sheathing. Category 8160 is the underside of horizontal projections. Perforated fiber-cement soffit is cladding. It is not an ember-resistant vent. HardieSoffit un-vented (8160-2026:0007) is an under-eave record, not an 8140 wall row.

Does IBHS Essential require noncombustible siding?

IBHS Wildfire Prepared Essential targets ember ignition and does not require noncombustible wall covering. Enhanced adds flame and radiant-heat items, including noncombustible wall covering. That is a designation, not adopted code.

Is SFM 12-7A-1 the Oregon wall test?

No. Where R327 is adopted, the performance wall path is ASTM E2707 for a 10-minute direct-flame exposure. ASTM says E2707 closely follows SFM 12-7A-1. They are not the same named protocol. OSFM 8140 rows name 12-7A-1. Deschutes County will use handbook products when they are shown on the drawings. That is local practice.

Is OSFM 8140 the same as 8170 or 8175?

No. Category 8140 is exterior wall siding and sheathing. Many rows name SFM 12-7A-1. Some 8140 rows name ASTM E136 instead. Category 8170 is ignition-resistant materials. Category 8175 is noncombustible materials. Read the category on the listing.

Where this answer differs

5 sourced rows

  • Model code 2018 IWUIC Class 1–2 noncombustible wall — The unamended 2018 IWUIC includes approved noncombustible material as an exterior-wall path in Class 1 and Class 2 construction.
  • Model code 2021 IWUIC Class 1–2 noncombustible wall — The unamended 2021 IWUIC includes approved noncombustible material as an exterior-wall path in Class 1 and Class 2 construction.
  • Model code IWUIC Class 1–2 noncombustible wall — The unamended 2024 IWUIC model code includes approved noncombustible material as an exterior-wall path in Class 1 and Class 2 construction.
  • Model code IWUIC Class 1 wall-base protection — The unamended 2024 IWUIC model code specifies a six-inch vertical metal or noncombustible wall-base detail at ground, deck, and roof intersections for Class 1 construction.
  • Voluntary program IBHS Base six-inch wall-base protection — The current IBHS Base standard specifies at least six vertical inches of noncombustible material at the base of exterior walls.