Residential Addition / Remodel Permit (including Basement Finish) in Lone Tree, Colorado

Lone Tree requires a residential addition / remodel permit (including basement finish) for: Permit required for additions, basement finish, and any structural alteration of an existing residential structure; Additions of 500+ square feet, or exterior wall replacement/repair of 25% or more, trigger Colorado Wildfire Resiliency Code mitigation if the parcel is in a mapped fire-intensity zone; A soils test (Colorado-registered PE) may be required at the Building Official's discretion depending on scope, per the same IBC 105.3.8 local amendment applied to new construction; Applications submitted via the Accela Citizen Access online portal. If your project isn't listed, confirm with City of Lone Tree Community Development Department, Building Division at 720-390-5211 before starting work.

In Lone Tree, the published Building/Mechanical/Electrical/Plumbing Permit Fee (same valuation-based schedule as new construction) is: $23.50 minimum, scaling per the valuation tiers in the 2026 Building Fees schedule. Additional published fees: Plan Review Fee — 65% of Permit Fee, minimum $100.00; City Use Tax — 2.5% of construction materials value. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Lone Tree does not publish a plan-review timeline for this permit. Contact City of Lone Tree Community Development Department, Building Division at 720-390-5211 for current turnaround.

You'll need: Building Permit Application; Construction Plan Set. See the required-documents checklist on this page for details on each.

Lone Tree requires 4 inspection(s) for a residential addition / remodel permit (including basement finish), in order: Foundation (additions with new footings only), Rough Frame, Rough Electrical / Plumbing / Mechanical, Final Inspection. Schedule each through City of Lone Tree Community Development Department, Building Division (720-390-5211).

Apply through City of Lone Tree Community Development Department, Building Division at 9220 Kimmer Dr., Suite 100, Lone Tree, CO 80124. Phone: 720-390-5211, email: building@cityoflonetree.com. Office hours: 7:00 AM - 4:00 PM, Monday-Friday, excluding holidays/weekends. Chief Building Official: Matt Archer. Community Development Director: Kelly First (kelly.first@cityoflonetree.com, 720-509-1274). General city line: 303-708-1818.. Official information: https://cityoflonetree.com/community-development/building/.

Lone Tree, Colorado has adopted: 2021 International Building Code (IBC), as amended — City of Lone Tree Design Criteria & Codes page; 2021 International Residential Code (IRC), as amended; 2021 International Fire Code (IFC); 2021 International Plumbing Code (IPC); 2021 International Mechanical Code (IMC); 2021 International Fuel Gas Code (IFGC); 2021 International Energy Conservation Code (IECC); 2023 National Electrical Code (NEC); 2017 ICC A117.1 Accessibility Code; Note on Chapter 18 (Building Regulations), Lone Tree Municipal Code: search-indexed content confirms the City has adopted the International Building Code, 2021 Edition, as amended, with a certified copy on file with the City Clerk; a local amendment adds Section 105.3.8 'Soils Test,' requiring a soils test prepared by a Colorado-registered professional engineer at building permit application, with an engineering geologist additionally required for hillside/geological-hazard/steep-slope sites at the Building Official's discretion. Full text of Chapter 18 could not be independently re-verified beyond this indexed excerpt because library.municode.com/co/lone_tree serves an Angular single-page app shell (empty of code text without JS rendering) and returned HTTP 403 to both a standard fetch and a full-browser-header curl retry — this is a partial-confidence caveat on the amendment-detail level only, not on the base code-edition list, which is independently confirmed on the City's own actively-maintained Design Criteria & Codes page.; HB22-1362 statewide energy floor (Colorado): as of 2026-07-06 (this review date), HB22-1362 requires that municipalities/counties updating their building code adopt an energy code achieving equivalent-or-better performance than the 2021 IECC + Model Electric and Solar Ready Code (effective window 7/1/2023-6/30/2026), stepping up to the Colorado Energy Code Board's Model Low Energy and Carbon Code (published 9/2/2025) as the new statewide minimum for any code update on or after 7/1/2026. Lone Tree's currently-published adopted energy code is the 2021 IECC (per its own Design Criteria & Codes page, most recent update not dated on-page) — this predates the 7/1/2026 Model Low Energy and Carbon Code trigger point and does not itself violate HB22-1362, since that stricter floor applies only when a jurisdiction next updates its code. Flagged honestly rather than assumed; confirm current status with the Building Division (720-390-5211) before relying on this for a 2026-cycle project, since Lone Tree could adopt updated codes at any time.. Local amendments apply — see the Lone Tree overview page for the full list.

Yes. The City's Do I Need a Building Permit guidance explicitly lists basement finish as an example of work requiring a building permit.