Do you need a permit to replace a roof in Unincorporated Jefferson County, CO?

Jefferson County, Colorado (unincorporated)

county

Golden, CO

Required

Reroofing in unincorporated Jefferson County requires a building permit from the Jeffco Building Division. Incorporated cities such as Lakewood, Arvada, Golden, and Wheat Ridge issue their own permits. Colorado has no statewide roofing contractor license.

2024 Jefferson County Building Code (the county's adoption of the 2024 I-Codes with local supplement), per the county’s "Important Notice on Roofing" dated July 1, 2026. (The notice PDF’s filename still says "2018-IRC" — the dated document body controls.)

Required About drip edge

Required — "Ice barrier shall be installed for asphalt shingles, metal roof shingles, mineral-surfaced roll roofing, slate and slate-type shingles, wood shingles and wood shakes per R905.1.2. Concrete and clay tile per manufacturer's instructions R905.3.8." (2026 county roofing notice does not restate a specific inside-wall distance beyond the R905.1.2 citation.) About ice & water barrier

Required — "A mid-roof inspection shall be required when the roof is at least 10 percent, but no more than 25 percent, completed per Jefferson County Supplement (R109.3.7)."

Not required — The 2024 Jefferson County Building Code Supplements, Fee Schedule and Fee Refund Procedure — the county's amendment package to the 2024 I-Codes, approved by the Board of County Commissioners on March 31, 2026 and effective for permits applied for on or after July 1, 2026 — was reviewed in full, including its Section R905 (Requirements for Roof Coverings) and Section R908 (Reroofing) amendments and the corresponding commercial amendments at Sections 1505 and 1512; it contains no impact-resistance or UL 2218 requirement, and it does not amend IRC Section R905.2.4. The county's separate Jefferson County Wildfire Resiliency Code, approved March 10, 2026 and made part of the Jefferson County Building Code by its Section 101.1, was also reviewed: its Section 402.2 (Roofing) requires a roof assembly "classified as Class A when tested in accordance with ASTM E108 or UL790" for structures in the Wildland-Urban Interface overlay, which is a fire classification rather than an impact rating. The county's "Important Notice on Roofing" dated July 1, 2026 likewise addresses asphalt shingle wind resistance under ASTM D7158 (G or H) or ASTM D3161 (A, D or F) and Class A fire assemblies in the WUI, and states no impact-resistance requirement. Class 4 impact-resistant shingles are therefore not required in unincorporated Jefferson County; incorporated cities within the county set their own requirements.

"Roof repairs less than 25% of the total roof area and not more than 2 squares are exempt from permit (R105.2 – Jefferson County Supplement)." A permit is required once a repair reaches 25% of total roof area or exceeds 2 squares (200 sq ft).

TABLE R301.2(1) - CLIMATIC AND GEOGRAPHIC DESIGN CRITERIA (Jefferson County Supplement to the 2024 International Residential Code, Section R301: Design Criteria): "Wind Design Speed (mph): 129 mph ** V ult Exp. B" ("** Approximately Equivalent to 100 mph Vasd (three second gust) Exposure B"); Wind Design Topographic Effects "Yes"; Seismic Design Category "B"; Ice Barrier Underlayment Required "Yes." Footnote exception: "Rocky Mountain Metropolitan Airport area between Simms St. and Wadsworth Blvd. and north of 108th Ave. shall be 155 mph Vult Exposure C (Approximately 120 mph three second gust Exposure C)." Independently corroborated for commercial structures at IBC Sec. 1609.3.2 (Jefferson County wind speed design criteria): "Allowable Stress Design Windspeed (Vasd): 100mph Exposure B; Basic Design Windspeed (V): 129 mph Exposure B" with the same airport-area exception (Vasd 120 mph / V 155 mph, Exposure C).

"SECTION R908: REROOFING. In section R908.4 (Roof recover) add a new Exception 4. as follows: Exceptions: 4. Where the existing roof covering is asphalt shingles." (Jefferson County Supplement to the 2024 IRC.) This bars roof recover/overlay over an existing asphalt shingle roof, so a full tear-off is required. The county's separate roofing notice restates the same rule in plain language: "Only one layer of asphalt shingles will be allowed per Jefferson County Code Supplement R908-4 exc.4 NO OVERLAYS, COMPLETE TEAROFF REQUIRED." An identical Exception 4 is added for commercial buildings at Section 1512.3 (Roof recover) of the Jefferson County Supplement to the 2024 IBC.

Unincorporated Jefferson County combined rate is 4.5% (state 2.9% + county 0.5% + RTD 1.0% + SCFD/CD 0.1%; all of Jefferson County lies within the RTD/CD boundary). Jefferson County is state-collected (not home-rule). Per the county's own FAQ, Jefferson County does not impose a use tax, so no county-level use tax is due on construction materials for permits in unincorporated Jefferson County (city use tax may still apply within incorporated cities).