Major 2021 Building Code Changes

Community Development Offices - System Update on November 25 & 26, 2024

The Larimer County Community Development Department (Building, Planning, Code Compliance) will conduct a system update on November 25 & 26. This update also affects groups outside of Community Development, including the Weeds District and Engineering. The Online Customer Portal is part of this update and will not be available. No inspections or permitting will take place online. Inspections will be performed on Monday, November 25. Staff on call will be available, but we cannot initiate new permits, code cases or zoning files or look up information regarding existing permits, code cases or zoning files, etc. Thank you for your understanding and we apologize for any inconvenience.

Codes Adopted as of 03/31/2022

2018 versions of first eight codes are repealed as of same 3/1/22 date. The 2021 ISPSC is a new code. 2020 NEC continues as our electrical code, now with an administrative section.

  • 2021 International Residential Code (IRC)
  • 2021 International Building Code (IBC)
  • 2021 International Energy Conservation Code (IECC)
  • 2021 International Existing Building Code (IEBC)
  • 2021 International Fuel Gas Code (IFGC)
  • 2021 International Mechanical Code (IMC)
  • 2021 International Plumbing Code (IPC)
  • 2021 International Property Maintenance Code (IPMC)
  • 2021 International Swimming Pool and Spa Code (ISPSC)
  • Administrative amendments to the 2020 National Electrical Code (NEC)

Significant Code Changes

Note: This is a partial list, sections not identified.

  1. Create a single set of administrative rules for IBC, IECC, IEBC, IFGC, IMC, IPC, IPMC and IPSC for improved consistency of administration. The IRC has its own, slightly different rules.
  2. Adopt a set of administrative rules for the NEC.
  3. Adopt the International Swimming Pool and Spa Code to put regulations in place for nonresidential pools. Pool barrier requirements also apply to residential pools 24” deep or more.
  4. Remove the local IRC amendments lowering the maximum square footage of accessory sheds and the height of fences that can be built without permits. [less than or equal to 200 sf / 7' high exempt].
  5. Premises identification signage must be installed during construction, containing the address and building permit number.
  6. Require newly constructed two-family dwellings, townhouses, and Short-term Rentals to install a fire-suppression sprinkler system, while continuing to exempt single-family dwellings outside of a Fire District with an adopted fire code requiring such sprinklers as approved by the Board of County Commissioners.
  7. Require installation of smoke and carbon monoxide alarms when adding, altering, or repairing plumbing or mechanical systems.
  8. Amend Wildfire Hazard Area requirements in both IBC and IRC to require the lowest 4’ of siding be noncombustible OR the first 5’ of ground cover around the structure be noncombustible. Require all additions to provide defensible space.
  9. Integrate rules for Estes Valley Vacation Homes into general code rules for Short-term Rentals and amend those rules as they relate to portable fire extinguishers, “dark sky” exterior lighting, and exterior solid fuel-burning appliances.
  10. Require Resort Lodge cottages with no more than 10 occupants and Owner-occupied Lodging Homes with no more than 5 bedrooms to comply with some of the Short-term Rental requirements.
  11. Require installation of passive radon mitigation systems for all newly constructed dwelling units or additions exceeding 1,000 sq. ft. in floor area, testing of radon levels before final inspection, and installation of an in-line fan if test shows radon levels above 4.0 pCi/L (picocuries per liter).
  12. Require all new dwelling units with an attached garage or carport be provided with a continuous 50-amp, 208/240-volt dedicated branch circuit for electric vehicle supply equipment at a vehicle parking space (“Electrical Vehicle Ready”).
  13. Require all new dwelling units be provided with a continuous 50-amp, 208/240-volt dedicated branch circuit from under the roof surface most likely to support photovoltaic panels or wind energy system to within 12” of the electrical meter or connected directly to the electrical panel board (“Renewable Energy Ready”).
  14. Require all roof coverings countywide to be minimum Class A fire-rated.
  15. Require new asphalt shingles roof covering to be Class 4 impact resistant.
  16. Increase minimum prescriptive ceiling insulation requirements to R-60, wall insulation requirements to R-30 cavity or R-20 cavity plus R-5 continuous exterior insulation, and basement/crawl space walls to R19 cavity or R15 continuous insulation.
  17. Require all permanently installed light fixtures to be “high-efficacy.”
  18. Open combustion fuel-burning appliances must be installed within enclosed mechanical rooms isolated from the building thermal envelope.
  19. All ducts, both inside and outside the thermal envelope, must be pressured-tested.
  20. Air leakage testers must be involved in the construction process at the beginning not the end, providing a report on air leakage deficiencies and corrections at the framing or insulation inspection.
  21. Only 2018 or 2021 RES-Check compliance reports will be accepted.
  22. Lower the square footage for commercial buildings exempt from mechanical and lighting systems commissioning from 15,000 to 10,000 sq. ft. in floor area.
  23. Appliance vents shall terminate at least 22” above grade and at least 12” above anticipated snow level.
  24. A return air path shall be provided from all habitable rooms by means of ducts or transfer grills.
  25. Manufactured homes installed at or above 6,000 ft. elevation or in High Wind Areas must install snow and wind mitigation measures pre-approved by the County Building Division.
  26. Updated accessibility standards for new construction require larger spaces for motorized wheelchairs including bathrooms, entrance and exit paths.