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Manufactured homes in fire country
A HUD manufactured home is a factory-built dwelling under 24 CFR 3280, not an ORSC R327 house. Oregon BCD and Deschutes County say manufactured dwellings are outside R327. Skirting, crawlspace vents, and dryer exhaust are HUD installation rules. A factory wildfire option or 13D sprinklers can still be real. So can Zone 0 around the unit. This page is the owner path. The finding is the code-scope record. Do not clone it.
You are looking at a HUD data plate in a closet, then at vinyl skirting with a dryer hose dumped under the floor, then at a neighbor who said “R327 doesn’t apply so you are done.” The data plate is the factory book. The skirting is the installation book. The five feet of bark is still fuel.
This page is the HUD owner path, not a site-built wall stack.
Why it matters
Owners hear “manufactured, so no wildfire code” and skip mesh, skirting vents, and the first five feet. Insurers still score the lot. Embers still go under the floor. R327’s silence is not a listing and not a clean bill.
How it works
HUD writes the construction standard (part 3280) and a model installation standard (part 3285). Oregon adds an installation code. The building official who stamps ORSC houses is not rewriting the HUD box. The installer still has to vent the crawl, keep wood skirting off the soil, and take dryer exhaust through the skirting, not into it.
HUD’s 2024 rule: sprinklers are not required in 3280.214. If the factory installs them as an option, the design has to meet HUD’s section. NFPA 13D’s scope includes manufactured homes. That is interior life safety, not R327 eaves.
The paths
| Book | What it decides | What it is not |
|---|---|---|
| 24 CFR 3280 | Factory construction, including optional sprinklers | ORSC R327 |
| 24 CFR 3285.504–.505 | Skirting and crawlspace vents if you skirt | Ember-rated eave vents |
| Oregon installation / local installer | Set, block, and utility hookup | A WUI wall listing |
| R327 | Site-built ORSC dwellings where adopted | This chassis |
| Lot / Zone 0 | Fuel in the first five feet | HUD flame-spread interior finish |
1. Read the data plate, not a Pinterest “park model.” If it is a HUD manufactured home, R327 is the wrong code book in Oregon. Confirm with the county. ADUs that are site-built are a different page: R327 ADUs and shops.
2. Skirt it so the crawl can breathe and embers have a harder path. Weather-resistant skirting. Wood within 6 inches of grade treated or naturally durable. Vents high, opposite sides, rodent-resistant covers, 1/150 (or 1/1,500 with a ground vapor retarder). Dryer and combustion air through the skirt. HUD does not print R327’s mesh range here. If you add finer mesh, do not starve the 1/150 area without doing the math.
3. Treat the lot like any other house. Bark against the skirt is still bark. See the hardening ladder and Zone 0.
4. Ask the carrier which document it scores. IBHS, a manufacturer wildfire package, and HUD construction are different files. Do not invent a listing ID.
5. Sprinklers are optional at the factory. If you want them, see 13D and wildfire. They do not replace skirt vents.
What people mix up
- Treating “not R327” as “not wildfire.”
- Dumping the dryer under the floor.
- Closing crawl vents in winter in a freeze climate without using HUD’s adjustable covers.
- Applying R327 eave rules to a HUD box as if it were ORSC.
- Calling a park-model RV a manufactured home.
How to check
- Open the HUD data plate.
- Open BCD’s local-adoption FAQ and the finding.
- Walk the skirt: dryer through, vents opposite, wood off grade.
- Walk the five feet.
- Ask the insurer which checklist it is using.
Limits
This page does not certify a HUD plant and does not design a foundation. The opened sources are 24 CFR 3285.504 and 3285.505 and HUD’s 2024 sprinkler rule. FireApproved is not HUD. Modular homes built to ORSC are not this page.
Related records
Questions
Does R327 apply to my manufactured home?
Oregon BCD’s local-adoption FAQ says R327 applies only to structures governed by the ORSC. Manufactured dwellings are factory-built to federal HUD standards plus an Oregon installation code. Deschutes County repeats that they are not applicable. See the finding manufactured homes outside R327.
What about skirting and underfloor vents?
HUD’s model installation standards (24 CFR 3285.504 and .505) govern skirting if you use it, crawlspace ventilation (one square foot of opening per 150 square feet of floor, or 1 per 1,500 with a ground vapor retarder), rodent-resistant covers, and dryer vents through the skirting to the outside. That is not R327.3.2.
Can I add sprinklers?
HUD’s 2024 construction-standards rule says fire sprinklers are not required by § 3280.214. If the manufacturer installs them as an optional feature, the system must meet HUD’s technical requirements. NFPA 13D’s scope includes manufactured homes. That is still not R327.
Does Zone 0 still matter?
Yes. Defensible space and the first five feet are lot rules and guidance, not HUD factory construction. See Zone 0 in California, Oregon, Firewise, and IBHS.