FireApproved

United States / Build / Fire-resistant decking

Fire-resistant decking

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 decking is a walking surface tested as an assembly, above an underfloor that is enclosed or protected. California's OSFM category 8110 lists boards tested to SFM 12-7A-4, a two-part test of under-deck flame and then a burning brand on the boards. Oregon R327, where adopted, accepts ASTM E2632/E2726 results, ignition-resistant material, exterior fire-retardant-treated wood, or noncombustible material for surfaces 30 inches to 12 feet above grade. A listed board does not finish the deck: the underfloor enclosure, the joists the listing names and the five-foot band under and around the deck are separate rules.

What the sourced rules ask for

For national decking, the national decking requirement is 2018 IWUIC Class 1–2 noncombustible deck. On national decking, it is shown as model code. Read the national decking rule, then compare 1 matched national decking product.

Review 18 national decking place answers before choosing among national decking records. The national decking 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 deck. The unamended 2018 IWUIC includes approved noncombustible materials as one path for attached unenclosed accessory structures and projections such as decks.

Products matching the model-code floor

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

No sourced decking product in this directory yet matches the model-code floor.

Additional products matching the voluntary program

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

Questions

What kind of decking is fireproof?

None. SFM 12-7A-4 in California and the R327 paths in Oregon classify how a walking-surface assembly performs under flame and a burning brand; they do not make a deck fireproof, and the underfloor and the five-foot band carry their own rules.

Is Trex decking fireproof?

No decking is fireproof. Named Trex models appear in OSFM handbook category 8110, tested to SFM 12-7A-4 or the 12-7A-4A alternate; that is a California listing for those models, not a fireproof claim and not an Oregon R327 pass by itself.

How to fireproof a wood deck?

You cannot. The sourced paths are a tested walking surface, an underfloor enclosed or protected to grade, no stored fuel beneath, and a noncombustible five-foot band; mesh laid flat under the boards is not one of them because it traps debris and leaves the side open.

Is Trex banned?

No. Named Trex models appear in OSFM handbook category 8110. An OSFM listing is a California BML record for those models, not a ban list and not an automatic Oregon R327 walking-surface pass. Match the model to the adopted code and the drawing.

Do I need an OSFM listed deck in Oregon?

Deschutes County says it will accept products from the OSFM WUI handbook, including decking, when those products are shown on the drawings. Oregon R327 walking-surface tests are not SFM 12-7A-4. Confirm with the building official.

Can I staple mesh under the deck boards?

No. Mesh laid horizontally under the walking boards traps debris and leaves the side open to embers. If you screen, close the vertical opening from the walking surface to grade. See Findings.

Does a listed board finish the deck?

No. The walking surface, the underfloor enclosure, the joists the listing names, and the five-foot band under and around the deck are separate. A board is not a complete deck specification.

Do stairs to an elevated deck have to match the walking-surface rule?

Deschutes County’s R327 FAQ says the code does not set stair-assembly rules for elevated decks and that Oregon BCD treats those stairs as exempt. Confirm with the building official. Do not import a stair rule from another state.

Where this answer differs

5 sourced rows

  • Model code 2018 IWUIC Class 1–2 noncombustible deck — The unamended 2018 IWUIC includes approved noncombustible materials as one path for attached unenclosed accessory structures and projections such as decks.
  • Model code 2021 IWUIC Class 1–2 noncombustible deck — The unamended 2021 IWUIC includes approved noncombustible materials as one path for attached unenclosed accessory structures and projections such as decks.
  • Model code IWUIC Class 1–2 noncombustible deck — The unamended 2024 IWUIC model code includes approved noncombustible materials as one path for attached unenclosed accessory structures and projections such as decks.
  • Voluntary program IBHS Base under-deck mesh — The 2025 IBHS Base standard specifies perimeter enclosure mesh for decks whose walking surface is four feet or less above ground.
  • Voluntary program IBHS Plus solid deck surface — The current IBHS Plus retrofit path specifies a solid noncombustible deck walking surface with no gaps.