Codes & Design Requirements

PLEASE NOTE, beginning October 26, 2022, the City of Helena Building Division will enforce the 2021 edition of the International Codes, Uniform Plumbing Code and the 2020 edition of the National Electrical Code along with the State of Montana, Administrative Rules amendments and as amended in City Code, Title 3. All permit applications received on or after October 26, 2022 will be reviewed under the newly adopted codes. For more information see Open Letter of Final Adoption(PDF, 169KB) or contact the City Building Division at (406) 447-8438.

The Building Codes listed below are effective as of October 26, 2022 The codes have been adopted and amended by the Administrative Rules of Montana (ARM) Title 24, Chapter 301, and adopted by the City of Helena in Title 3 of the City Code.

• 2021 International Building Code - IBC
• 2021 International Residential Code - IRC
• 2021 International Mechanical Code - IMC
• 2021 International Fuel Gas Code - IFGC
• 2021 International Existing Building Code - IEBC
• 2021 Uniform Plumbing Code - UPC
• 2020 National Electrical Code - NEC (NFPA 70)
• 2021 International Energy Conservation Code - IECC (Effective July 21, 2021)
• 2021 International Fire Code - IFC
  • City of Helena Fire Code Amendments(PDF, 405KB)
• 2021 International Swimming Pool and Spa Code - ISPSC

Design Requirements

• Seismic Design Category according to the 2018 International Building Code (IBC), typically D0 or as calculated by International Building Code, Chapter 16 based on site specific soil conditions.
• Wind Load - f 3s - 90 mph, f fm - 75 mph
• Snow Load - (ground/roof) 30 lbs psf minimum
• Frost Depth - 42" minimum to bottom of footing
• Ice and Water Barrier Under-layment Required – Yes