Boulder, CO Building Safety: Building Permits (2026)

BRC 10-5-2 adopts the 2024 International Building Code by reference as the City of Boulder Building Code, with local amendments layered on top of the base IBC text. 2, 'Work exempt from permit,' as repealed and reenacted by 10-5-2(j), spells out that exemptions from the permit requirement do not authorize any work done in violation of the code or other city ordinances, then lists what does not need a permit: one-story detached, non-conditioned accessory buildings of 120 square feet or less and no taller than ten feet with no electrical, mechanical, or plumbing service; fences no more than 7 feet high; retaining walls no more than 3 feet from footing to top unless they hold back a surcharge or Class I-III-A flammable liquids; walks and driveways no more than 30 inches above grade; finish work like painting and flooring; small prefabricated pools under 5,000 gallons and less than 24 inches deep; and single-family or townhome decks of 200 square feet or less that sit no more than 30 inches above grade, aren't attached to the dwelling, and don't serve a required exit door.

Everything outside that list, additions, new construction, garages over 120 square feet, structural alterations, needs a permit. Under 10-5-2(k), no permit can issue until every applicable city or Boulder County department signs off, including building, flood control, utilities, health, fire, engineering, zoning, planning, parks, and the city clerk. Applications go stale after 180 days without action (10-5-2(l)), and issued permits expire if work doesn't start within 180 days or stalls for 180 days (10-5-2(m)), with a hard three-year cap from issuance to occupancy approval.