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Building Inspection Division

The Building Inspection Division is responsible for the Plan Review, Permit Issuance and Inspection of new construction projects and remodel of existing structures in the City of Thornton.

Office Hours are 8:00 a.m. to 5:00 p.m. Monday through Friday.  Payments at the counter are accepted 8:00 a.m. to 4:30 p.m. Payments can be made through the online portal at any time. 

Notice: As of May 6th, 2024 there will be a service charge added for every payment made by debit/credit card. The service fee, paid directly to the card processor, will be 3.15%. Please note this charge is for payments by debit/credit cards only. Alternative payment types; ACH (echeck - which can be paid through the portal), checks, and cash will continue to be accepted without additional service fees.




Schedule your inspections online through our CityView PortalYou will need to register on the portal in order to schedule inspections. Make sure to follow the instructions for registration under the Portal Help menu. If you are a contractor you will need to log in using your company login. You can also schedule inspections through the Inspection Request Line 303-538-7396.  For roofing inspections only call 303-538-7430.

EFFECTIVE 8/01/2022 the cutoff time for requesting next business day inspections will be 3:30 pm.

Please leave the following information in this order when scheduling your inspection. It is advised that a landline be used to request your inspection rather than a cell phone.

  • Permit Number
  • Project Address
  • Type of Inspection
  • Let us know if this is a Re-inspection

Access must be provided to all areas or items needing inspection. If we need access to your back yard to complete the inspection, please give us verbal permission in the request.

  • Please make sure that there are no animals in the back yard.
  • An adult at least 18 years of age shall be present for all required interior inspections.
  • Consultation inspections are available to any permit holder. If the inspection is not available on the permit please call 303-538-7250.

Weather and Cancellations

  • In the event of ice, snow, wind or other weather event, inspections may be cancelled if it is determined that they cannot safely continue.  Cancellations are generally not automatically rescheduled. Please refer to the portal to view inspection results and/or reschedule inspections.

In addition, the following policies regarding inspections have been put in place.

Contemporaneous Reviews Policy


Please click on the topics below to learn more about each section.

 Occupied Structure Inspections (Homeowner projects and remodels, Commercial TI projects)

We have resumed in-person inspections within occupied structures and will attempt to accommodate the homeowner based on their comfort level with in-person inspections. If a virtual inspection is preferred, please clarify such when scheduling the inspection (**see virtual inspection guidelines below). We will continue to provide in-person inspections for work being done outside of the occupied structure (i.e. fences, detached garages, etc.).

 **Virtual Inspections (Video Call)

The following is a list of what we believe could be inspected via virtual inspection in an occupied structure: caisson, footing, stem wall, water heater, furnace, AC, rough inspections, drywall, final inspections, final deck/ patio cover, driveway, and fence.

All Roof inspections and Solar PV inspections will be done virtually. Onsite contact information must be provided when scheduling.

Basement finish re-inspections may be scheduled for virtual inspection and will be left to the discretion of the inspector whether an inspection can be completed. 

*The exception to this rule will be when there is an inspection that is specifically related to safety/health in occupied structures.

**Before scheduling a virtual inspection, please verify you have the following:

  • Facetime or Google Meets app installed on your mobile device,
  • Wi-Fi connection (be sure the signal works outdoors as you will be asked to verify your address in the video)
  • Have inspection tools available (tape measure, level, flashlight, GFCI capable outlet tester, step ladder)
  • When scheduling the inspection, provide name and phone number of the person operating the camera. If this information is not provided the inspection will be automatically canceled and you will need to reschedule it.

NOTE: If at any time the inspector believes they cannot complete an inspection virtually due to poor signal, or other reason they may require the inspection be rescheduled at a later date and/or in-person.

CO Routing Prior to Final Inspection

Required only for Commercial, Multi-family, and Single Family Attached Shell Permits. To begin the routing process please call 303-538-7250 one week prior to requesting final inspections.

Fire Department Information

The Fire Prevention Division is responsible for the enforcement of City of Thornton laws, codes, and ordinances, including the International Fire Code and nationally recognized standards. Through plan review, inspections, meetings with citizens and design professionals, and continuing education, the Prevention staff works toward the protection of life and property from the effects of fire. For questions regarding fire permits contact the Fire Department directly at 303-538-7602.

Roofing/Re-roofing Standards

The City of Thornton has amended the roofing sections of the International Building Code and the International Residential Code to require asphalt shingles to carry a manufacturer's national wind warranty for the City’s designated wind speed of 90 mph 3-Second Gust. Please see our Roofing Standards for a list of approved shingles and other roofing requirements.  

Please click here to read the Roofing Inspection Policy effective 3/5/2024.

Permit Information

A building permit is required any time you erect, construct, enlarge, remodel, alter, repair, move, improve, remove, convert, demolish, or change the type of occupancy of any building, structure or utility. For a list of projects that require a permit and a list of projects that do not require a permit, click on the Building Permit Requirements link listed under the Permits, License Application section of links.

The process to obtain a permit will vary dependent upon the complexity of the project.  It is our goal to get plans through the system and a permit issued in the minimum amount of time possible.

Plan Review

Once you have all of the information gathered for a complete submittal package the application and plans can be submitted electronically through the CityView Portal.  Refer to the Submittal Requirement links on the right hand panel for more information.

The amount of time to process and review a plan from the initial submittal date to the completion of the first review (the turn around time) will vary with the type of project. Delays may occur due to high volume of applications.

  • New Commercial -  18  working days or less
  • Commercial Tenant Improvements & Remodels - 13 working days or less
  • New Residential except multifamily - 13 working days or less
  • Residential Remodels and Misc. - 8 working days or less

Permit Issuance

Once all approvals have been completed, the application is prepared for permit issuance by the permit technician staff.  They will verify that all contractors are currently licensed, all permission forms have been received and calculate the permit fee.  Once this is complete, you will be notified that the permit is ready for issuance.  Following payment of fees, you can access the building permit, required inspection and the approved plans by accessing the permit in the online portal.

Code & Amendments

Adopted Codes for the City of Thornton

  • 2021 International Building Code
  • 2021 International Residential Code
  • 2021 International Plumbing Code
  • 2021 International Mechanical Code
  • 2021 International Fuel Gas Code
  • 2021 International Existing Building Code
  • 2021 International Energy Conservation Code
  • 2021 International Swimming Pool and Spa Code
  • 2021 International Fire Code
  • 2020 National Electric Code