Unincorporated Jefferson County enforces the 2024 IRC with a county supplement effective July 1, 2026, and you need a permit unless a repair is under 25% of the roof and no more than 2 squares. The supplement bars recovering over asphalt shingles and requires a mid-roof inspection at 10 to 25% complete.
General information, read from the official sources listed below on 2026-10-28. Codes and local policies change, so confirm the rules for your address with the building department before work starts.
Jefferson County (unincorporated) roof code data table
| Item | Jefferson County (unincorporated) |
|---|---|
| Adopted IRC edition | 2024 IRC with the 2024 Jefferson County supplement. Source: 2024 Jefferson County Building Code Supplements (effective 7/1/2026) |
| Adopted IBC edition | 2024 Building Codes package approved by the county. Source: Jefferson County adopted building codes |
| Adoption or effective date | Approved by the Board of County Commissioners March 31, 2026; supplement effective July 1, 2026 (2018 codes applied until June 30, 2026). Source: Jefferson County adopted building codes |
| Roofing amendments and local policies | R908.4 Exception 4: no recover where the existing covering is asphalt shingles. R905.2.8.3 rewritten: step flashing at least 4 x 4 in with the vertical leg continuous under siding; counterflashing at masonry per R703.8.2.2. Drip edge at eaves and gables. Shingles ASTM D7158 G or H, or D3161 A, D or F. Contact the county before adding tile dead load. Source: 2024 Jefferson County Building Code Supplements (effective 7/1/2026) |
| Ice barrier rule | Required (Table R301.2: Yes) for asphalt, metal shingles, roll roofing, slate and wood; tile per the manufacturer. Source: Jefferson County roofing requirements notice (July 1, 2026) |
| Ground snow load | By elevation (Table R301.2.3): 43 psf ground / 30 psf roof below 6,500 ft, rising to 70 psf ground at 7,625 ft. Above 70 psf, the building must be engineered. Source: 2024 Jefferson County Building Code Supplements (effective 7/1/2026) |
| Design wind speed | 129 mph Vult, Exposure B countywide (about 100 mph Vasd); 155 mph Vult, Exposure C near Rocky Mountain Metropolitan Airport (Simms St. to Wadsworth Blvd., north of 108th Ave.). Source: 2024 Jefferson County Building Code Supplements (effective 7/1/2026) |
| Reroof permit trigger | Exempt: roof repairs under 25% of the total roof area and not more than 2 squares (R105.2 item 13). Everything else needs a permit; each structure needs its own. Source: 2024 Jefferson County Building Code Supplements (effective 7/1/2026) |
| Layers allowed | One. No overlays; complete tear-off required. Source: Jefferson County roofing requirements notice (July 1, 2026) |
| Wildfire / WUI code status | Class A roof assemblies required in the WUI Overlay District (county Wildfire Resiliency Code Section 402.2). Updated wildfire rules and a new overlay map apply to permits applied for as of July 1, 2026. Source: Jefferson County Re-Roofing |
| Inspection requirements | Mid-roof when the roof is more than 10% but less than 25% complete, plus a final. Photo inspections are not accepted. The permit card must be visible from the street. Source: Jefferson County Re-Roofing |
| Permitting office | Jefferson County Building Safety, 100 Jefferson County Pkwy, Suite 3540, Golden. Phone 303-271-8260, Monday to Thursday, 8 a.m. to 5 p.m. Source: Jefferson County Re-Roofing |
What it means for a homeowner reroofing in Jefferson County (unincorporated)
These rules apply outside city limits: Evergreen, Conifer-area mountain homes, Columbine and other unincorporated areas. Lakewood, Arvada and Golden have their own building departments and their own pages here.
Snow load is the number that changes most from house to house. The county table starts at 43 psf below 6,500 feet and steps up every 125 feet of elevation to 70 psf at 7,625 feet. Above that, an engineer designs the load, which matters for any heavier roof.
The county inspects in person only. Plan for a mid-roof visit early, between 10 and 25% complete, and keep the permit card visible from the street. A local fire protection district can also enforce its own standards, so mountain properties should check both.
Common inspection failures in Jefferson County (unincorporated)
These are items the building department's own code or handouts say it checks or rejects. No public data ranks how often each one fails, so the order means nothing.
- Asphalt shingles laid over existing asphalt.
- Step flashing under 4 x 4 in, or not interlaced with each course at a rake wall.
- Mid-roof requested after the roof passed 25%.
- Photos sent instead of an in-person inspection.
- Permit card not posted where the street can see it.
- Class B or C covering on a parcel in the WUI Overlay District.
Steps to permit a reroof in Jefferson County (unincorporated)
- Confirm the address is unincorporated Jefferson County, not inside a city.
- Check the WUI Overlay District map and the elevation snow table.
- Apply through the county citizen portal, one permit per structure.
- Request the mid-roof at 10 to 25% complete, by 5 p.m. the business day before.
- Pass the final and keep the signed green sticker on the permit card.
Related pages
- Evergreen roofing
- Colorado Wildfire Resiliency Code on a reroof
- Roof replacement
- Roof repair
- Hail damage repair
- Free roof inspection
- Compare roof codes by jurisdiction
Hail history by ZIP in Jefferson County (unincorporated): 80123 (Columbine), 80127 (Dakota Ridge), 80403 (Coal Creek), 80439 (Evergreen)
Sources
- 2024 Jefferson County Building Code Supplements (effective 7/1/2026)
- Jefferson County adopted building codes
- Jefferson County roofing requirements notice (July 1, 2026)
- Jefferson County Re-Roofing
Compiled by Integrity Roofing and Painting, roofing Colorado homes since 1990 (36 years in business). We are an Owens Corning Platinum Preferred contractor with 650+ Google reviews, and our repair scopes follow the local code and the manufacturer's installation and warranty requirements. We do not issue permits or rule on code; the building department does.
