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Commercial Tenant Improvement Permit in Thornton, Colorado

Required for tenant finish and remodel work in commercial spaces in Thornton. Reviewed by the City Development Building Inspection Division against the currently adopted commercial codes (2024 IBC/IMC/IPC/IFGC with Thornton amendments, effective July 1, 2025); Thornton publishes a target first-review timeline of 13 working days or less.

Verified 2026-06-30 · Source

When you need this permit

  • Complete permit application online via the CityView Portal (registered account required)
  • One set of construction drawings required, including a code analysis on the title page, floor plan, wall sections, electrical one-line diagram, mechanical plan, plumbing plan, special systems plan, and (if exterior changes) elevation plans, plus a site plan showing the project's location relative to the building and parking areas
  • All plans must bear the original seal and signature of a design professional
  • Special Systems plans include fire-rated assemblies, fire stopping, fire/smoke dampers, hood systems, and grease traps/interceptors
  • Fire protection system plans must be submitted to and approved by the Fire Department prior to permit issuance
  • A complete Com-Check report based on the currently adopted Energy Code, bearing the seal/signature of the mechanical engineer, is required
  • A completed water meter form bearing the mechanical engineer's original seal and signature is required
  • Code analysis must include occupancy group, construction type, number of stories, building height, actual/allowable floor area, occupant load, exit count/width, and required plumbing fixture calculations
  • Permit is not automatically issued — application is reviewed for approval, then payment is made, then the permit is processed and issued

Required documents

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Fee schedule

Building Permit Fee — valuation-based (same table as new construction)City of Thornton 2026 Building Permit Fee Schedule Table 1; commercial tenant finish valuation follows the same schedule as residential
Varies by valuation — $30.00 minimum up to $5,615.25 + $3.75/$1,000 over $1,000,000
Plan Review Fee
65% of the Building Permit Fee
Mechanical, Electrical & Plumbing trade permit feesApplies separately for each trade (mechanical, electrical, plumbing) included in the tenant finish scope
$30.00 for the first $1,000 of trade valuation, plus $10.00 for each additional $1,000 or fraction thereof, per trade

Review timeline

Plan reviewThornton’s published plan-review target
1–13 business days

How long did your Commercial Tenant Improvement Permit permit actually take in Thornton?

Anonymous — one question, no email. Answers are combined and only shown once at least 5 people have reported.

Inspection process

  1. 1

    Framing / Structural

    After framing complete, before walls covered

  2. 2

    MEP Rough-In

    Mechanical, electrical, plumbing rough-in before walls closed

  3. 3

    Fire Inspection

    Fire alarm, sprinkler, and suppression system inspections coordinated with the Fire Department

  4. 4

    Final / Certificate of Occupancy

    All work complete, life safety systems functional

See the full Thornton inspection guide — scheduling & re-inspection fees →

Tips

  • Thornton publishes a target first-review timeline of 13 working days or less for commercial tenant improvements and remodels — request current SLA status from Building Inspections if your project is time-sensitive.
  • The permit is NOT automatically issued after submittal — it goes through review and approval first, then payment, then issuance; budget for this sequencing when scheduling contractor start dates.
  • Fire protection system plans must be separately submitted to and approved by the Fire Department before the building permit can be issued — start this track in parallel with your building plan submittal.

Frequently asked questions

Thornton requires a commercial tenant improvement permit for: Complete permit application online via the CityView Portal (registered account required); One set of construction drawings required, including a code analysis on the title page, floor plan, wall sections, electrical one-line diagram, mechanical plan, plumbing plan, special systems plan, and (if exterior changes) elevation plans, plus a site plan showing the project's location relative to the building and parking areas; All plans must bear the original seal and signature of a design professional; Special Systems plans include fire-rated assemblies, fire stopping, fire/smoke dampers, hood systems, and grease traps/interceptors; Fire protection system plans must be submitted to and approved by the Fire Department prior to permit issuance; A complete Com-Check report based on the currently adopted Energy Code, bearing the seal/signature of the mechanical engineer, is required; A completed water meter form bearing the mechanical engineer's original seal and signature is required; Code analysis must include occupancy group, construction type, number of stories, building height, actual/allowable floor area, occupant load, exit count/width, and required plumbing fixture calculations; Permit is not automatically issued — application is reviewed for approval, then payment is made, then the permit is processed and issued. If your project isn't listed, confirm with City of Thornton — City Development, Building Inspection Division at 303-538-7250 before starting work.

In Thornton, the published Building Permit Fee — valuation-based (same table as new construction) is: Varies by valuation — $30.00 minimum up to $5,615.25 + $3.75/$1,000 over $1,000,000. Additional published fees: Plan Review Fee — 65% of the Building Permit Fee; Mechanical, Electrical & Plumbing trade permit fees — $30.00 for the first $1,000 of trade valuation, plus $10.00 for each additional $1,000 or fraction thereof, per trade. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Thornton publishes a target first-review timeline of 13 working days or less for commercial tenant improvement and remodel permits, per the City's Plan Review Submittal Requirements document.

You'll need: Commercial Tenant Finish Permit Application (CityView Portal); Plan Review Submittal Requirements — Commercial Tenant Finish; Com-Check Report. See the required-documents checklist on this page for details on each.

Thornton requires 4 inspection(s) for a commercial tenant improvement permit, in order: Framing / Structural, MEP Rough-In, Fire Inspection, Final / Certificate of Occupancy. Schedule each through City of Thornton — City Development, Building Inspection Division (303-538-7250).

Apply through City of Thornton — City Development, Building Inspection Division at 9500 Civic Center Drive, Thornton, CO 80229. Phone: 303-538-7250, email: buildings@thorntonco.gov. Office hours: Mon–Fri, 8:00 a.m.–5:00 p.m. (counter payments 8:00 a.m.–4:30 p.m.). Official information: https://www.thorntonco.gov/business-development/city-development/building-permits-inspections.

Thornton, Colorado has adopted: 2024 International Building Code (IBC) — with Thornton amendments; adopted by ordinance May 13, 2025, effective July 1, 2025 (replaced the 2021 IBC); 2024 International Residential Code (IRC) — with Thornton amendments (Table R301.2 climatic/geographic design criteria repealed and reenacted with Thornton-specific values); effective July 1, 2025; 2024 International Plumbing Code (IPC) — with Thornton amendments; effective July 1, 2025; 2024 International Mechanical Code (IMC) — with Thornton amendments; effective July 1, 2025; 2024 International Fuel Gas Code (IFGC) — with Thornton amendments; effective July 1, 2025; 2024 International Energy Conservation Code (IECC) — adopted in full (residential provisions); includes Colorado Model Electric Ready and Solar Ready Code per HB22-1362; effective July 1, 2025; 2024 International Existing Building Code (IEBC) — with Thornton amendments; effective July 1, 2025; 2024 International Swimming Pool and Spa Code (ISPSC) — adopted by reference; effective July 1, 2025; 2023 National Electrical Code (NEC) / NFPA 70 — Thornton adopts the NEC edition currently adopted by the State of Colorado automatically and simultaneously (Thornton City Code Sec. 10-162); matches the statewide electrical code; 2021 editions of the above I-Codes and the 2017 NEC — the prior code cycle, superseded for new submittals as of July 1, 2025 but referenced for projects permitted under it (e.g., the city's 2023-dated Solar PV submittal-requirements handout still cites 2020 NEC/2021 IRC/2021 IBC/2021 IFC and should be read as superseded by the current 2024/2023 code cycle for design-code citations). Local amendments apply — see the Thornton overview page for the full list.

One set of construction drawings including a code analysis, floor plan, wall sections, electrical one-line diagram, mechanical plan, plumbing plan, special systems plan (if applicable), elevation plans (if exterior changes), and a site plan — all bearing the seal and signature of a design professional, plus a Com-Check energy report and a water meter form.

Sources & verification

Verified against official sources. Last reviewed 2026-06-30.

Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Thornton building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.

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