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Oregon defensible-space checklist
The Oregon State Fire Marshal’s homeowner checklist is a walk-the-yard list, not R327. It wants 10 feet from buildings and chimneys, limbs at 6 feet on trees over 18 feet or one-third height on shorter trees, 1/8-inch mesh, vegetation 5 feet from the structure, and 100 feet of defensible space or to the property line. CAL FIRE’s 3-times-shrub-height ladder rule is a different picture. Confirm with the fire agency.
You are in the yard with the four-page checklist. Start at the gutter, then the first 5 feet, then the trees you can walk to. This is not a plant catalog and not a permit.
No g3-passed exhibit matches this checklist. ZON-012 is the CAL FIRE / IBHS ladder pair. Do not reuse it as the OSFM 6-foot drawing. Do not scrape OSFM’s page-2 art.
Why it matters
A weekend on this list is how needles leave the gutter and juniper leaves the wall. It is not how you pass plan review. Mixing OSFM’s 6-foot limb line with CAL FIRE’s 3-times shrub line is how a tree gets butchered or left as a ladder.
How it works
OSFM defines defensible space on the checklist as any area where combustible materials are treated, cleared, or modified to slow wildfire and leave room for suppression. Ladder fuel is low-hanging branches, leaves, needles, and other matter that can carry fire from low plants to high plants. The numbers on page 2 are that agency’s best-practice picture. They are not adopted R327.
How the documents split
| Object | OSFM checklist (Version 1) | What it is not |
|---|---|---|
| Limbing | 6 ft if the tree is over 18 ft; one-third height if under 18 ft | CAL FIRE 3× shrub height |
| Trees vs the house | 10 ft from buildings and chimneys | Cohen’s ~40 m home-ignitability distance |
| Tree to tree | 10 ft | IBHS crown spacing |
| First 5 ft | Flammable vegetation off the structure under eaves | IBHS Zone 0 as a whole hardscape spec |
| Mesh | 1/8 in metal wire | The only R327 vent path |
| Defensible space | 100 ft or to the property line | A statewide enforcement map |
| Grass | Under 4 in | A plant-list pass |
| Firewood | 30 ft from structures | A tank setback |
| Propane | Combustible vegetation 10 ft from permanent tanks | NFPA 58 table (not opened here) |
The paths
1. Walk structure first. Roof and gutters clean. Vegetation 5 feet off the wall under eaves. Mesh on attic, soffit, and under-deck openings. Siding sound. Debris off decks and fences. A metal gate or other noncombustible run where the fence hits the house. How clean is clean enough. Fence as a wick. Mesh versus listed vents.
2. Then walk 100 feet or to the line. OSFM. Spaced and pruned as on their page 2. Debris off the ground. Grass under 4 inches. Fire-resistive plants are a pointer to OSU’s guide, not a substitute for the plant records.
3. Limb the Oregon way on this sheet. Over 18 feet tall, 6 feet of clearance. Under 18 feet, one-third the height. Powerline work is a licensed contractor. Ladder fuels stays the CAL FIRE / IBHS picture.
4. Tanks and woodpiles are distances. Firewood 30 feet. Permanent propane, 10 feet of combustible vegetation off the tank. Unused BBQ cylinders 30 feet or in an outbuilding. This page does not reprint NFPA 58.
5. Access is the last box. Driveway clear, height and width per the local fire agency, address at the entrance. Fire apparatus access. Address signs.
6. Do not treat the list as Zone 0 law. Zone 0 is IBHS and California credit language. OSFM’s 5 feet is vegetation under eaves on this checklist.
What people mix up
- This checklist as R327.
- OSFM 6-foot limbs as CAL FIRE’s 3× shrub rule.
- 1/8-inch mesh as the only legal vent.
- 10 feet from the house as Cohen’s 40 meters.
- 100 feet as a permit condition on every Oregon lot.
- Scraping OSFM’s drawings onto a site plan.
How to check
- Open the OSFM PDF. Version 1 on the footer.
- Check roofs, 5 feet, mesh, fence, then 100 feet.
- Measure tree height before you limb. Over or under 18 feet changes the number.
- If you are scoring IBHS or California, open those pages. Do not use this checklist as their worksheet.
- If the lot has adopted R327, spec the covering and the vent from that code, not from 1/8-inch mesh on this list.
- Follow evacuation orders. The checklist says the recommendations do not eliminate the threat.
Limits
This page does not replace a free OSFM or partner assessment. It does not adopt a defensible-space code for your city. FireApproved is not OSFM. Keep the checklist in hand and confirm with the local fire agency. Who walks the yard, and whether that walk is free, is who can do a defensible-space assessment. When the same lot also has a tree-preservation condition, see defensible space vs tree preservation.
Related records
Questions
Is this checklist Oregon R327?
No. R327 is construction where a local department adopted it. The OSFM checklist is public defensible-space guidance. It says following the recommendations can increase the chance the house survives, and that you should still follow evacuation orders.
Is the 6-foot limb height the same as CAL FIRE’s 3-times rule?
No. OSFM’s page 2 says trees more than 18 feet tall, remove limbs up to 6 feet; trees less than 18 feet, remove limbs up to one-third the height. CAL FIRE’s ladder-fuel example is three times the shrub height between the shrub and the lowest branch. Do not merge those pictures. See ladder fuels.
Does 1/8-inch mesh satisfy R327?
Not automatically. The checklist recommends 1/8-inch metal wire mesh on attic vents, soffit vents, and areas below decks. Oregon R327 has its own vent paths, including listed ember- and flame-resistant vents and a mesh size range. See mesh versus listed vents.
Is 5 feet from the structure Zone 0?
OSFM recommends removing flammable vegetation from growing directly under the eaves, with a minimum of 5 feet from the structure. IBHS and California Safer from Wildfires treat Zone 0 as largely noncombustible. Oregon R327 does not print Zone 0. Cite the document you are scoring.