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Eaves

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.

What the sourced rules ask for

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

Review 18 national eaves place answers before choosing among national eaves records. The national eaves 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 “Eaves and soffits shall be protected on the exposed underside by ignition-resistant materials”

2018 IWUIC Class 1 noncombustible eave. The unamended 2018 IWUIC permits ignition-resistant material on the exposed underside of Class 1 eaves and soffits; Section 503.2 includes noncombustible material in that class.

Products matching the model-code floor

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

Additional products matching the voluntary program

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

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

Questions

What is the Oregon 12-foot rule for eaves?

Two rules share the number. R327.3.2.1, where adopted, does not allow ordinary vents on the underside of eaves, soffits, or cornices unless the opening is 12 feet or more above grade or the vent is manufactured to resist flame and embers. R327.3.4.1 requires protection of exposed rafter or truss undersides and enclosed soffits when any portion of that framing is under 12 feet. Deschutes County says there is no 12-foot exception for the underside of elevated decks.

Is vented fiber-cement soffit an ember-rated vent?

No. Perforated or louvered fiber-cement soffit is cladding. It is not 1/16–1/8 inch mesh and it is not an ASTM E2886 listed vent. OSFM 8160 listings for HardieSoffit and CemSoffit on this site are the un-vented under-eave material. See Findings.

What is OSFM 8160?

It is the California OSFM handbook category for horizontal projection undersides, including eaves. Many rows name SFM 12-7A-3. Some rows are listed as noncombustible under-eave material. It is a soffit or underside assembly, not a vent. Category 8165 is vents.

Is SFM 12-7A-3 the same as ASTM E2957?

No. SFM 12-7A-3 is the California underside test. Many OSFM 8160 rows name it. Oregon R327, where adopted, names ASTM E2957 among other covering paths. Deschutes County counts handbook products when they are shown on the drawings. The building official still decides.

Do I have to box in open rafter tails?

Where R327 is adopted and any of the eave framing is under 12 feet, you must protect the underside. Enclosure is one way. The code also allows noncombustible covering, ignition-resistant covering, 5/8 inch Type X gypsum behind the covering, a one-hour assembly, or an ASTM E2957-tested soffit. Fascia is exempt. A 4x tail is seminar practice, not a fifth numbered eave item. See the Craftsman eaves guide. IBHS Enhanced and California Safer from Wildfires ask for enclosed eaves. That is a checklist, not the R327 wording.

Does IBHS Essential require enclosed eaves?

No. Essential targets ember ignition at the roof, vents, gutters, and Zone 0. Enclosed eaves are an Enhanced item. They are also a California Safer from Wildfires insurance measure. They are not the Oregon code floor.

Where this answer differs

7 sourced rows

  • Model code 2018 IWUIC Class 1 noncombustible eave — The unamended 2018 IWUIC permits ignition-resistant material on the exposed underside of Class 1 eaves and soffits; Section 503.2 includes noncombustible material in that class.
  • Model code 2018 IWUIC Class 2 solid eave enclosure — The unamended 2018 IWUIC specifies solid material at least three-quarter inch thick around combustible eaves, fascias, and soffits in Class 2 construction.
  • Model code 2021 IWUIC Class 1 noncombustible eave — The unamended 2021 IWUIC permits ignition-resistant material on the exposed underside of Class 1 eaves and soffits; its ignition-resistant-material definition includes noncombustible material.
  • Model code 2021 IWUIC Class 2 solid eave enclosure — The unamended 2021 IWUIC specifies solid material at least three-quarter inch thick around combustible eaves, fascias, and soffits in Class 2 construction.
  • Model code IWUIC Class 1 noncombustible eave — The unamended 2024 IWUIC model code permits ignition-resistant material on the exposed underside of Class 1 eaves and soffits; Section 503.2 includes noncombustible material in that class.
  • Model code IWUIC Class 2 solid eave enclosure — The unamended 2024 IWUIC model code specifies solid material at least three-quarter inch thick around combustible eaves, fascias, and soffits in Class 2 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.