Montana building code
Montana has adopted 2021 IBC. The table below lists the governing edition for every discipline a plan check touches, followed by the Montana cities and counties that amend it locally.
- Current edition
- 2021 I-Codes with Montana amendments (ARM Title 24, ch. 301), effective June 11, 2022; 2020 NEC; 2021 UPC; 2021 IFC (State Fire Marshal, eff. March 11, 2023)
- Code authority
- Montana Department of Labor & Industry, Business Standards Division, Building & Commercial Measurements Bureau (Building Codes Program); fire code adopted by the State Fire Marshal, Montana Department of Justice
Adopted code by discipline
| Discipline | Adopted code | Local amendment |
|---|---|---|
| Building | 2021 IBC | n/a |
| Residential | 2021 IRC | n/a |
| Existing buildings | 2021 IEBC | n/a |
| Fire | 2021 IFC | n/a |
| Electrical | 2020 NEC based on NFPA 70-2020 | n/a |
| Mechanical | 2021 IMC | n/a |
| Plumbing | 2021 UPC based on 2021 UPC (IAPMO) | n/a |
| Energy | 2021 IECC | n/a |
| Accessibility | 2017 ICC A117.1 based on ICC A117.1-2017 | n/a |
| Wildland-urban interface | 2021 IWUIC | n/a |
| Fuel Gas | 2021 IFGC | n/a |
Overlays that can apply
Mapped hazard and district overlays stack on top of the adopted code. These are the overlays recorded for Montana. They apply by parcel, not jurisdiction-wide, so confirm the parcel before assuming one is in play. Check CAL FIRE's fire hazard severity viewer and FEMA's flood map service.
- Wildland-urban interface area
- Seismic design category overlay
Sources
- https://bsd.dli.mt.gov/building-codes-permits/current-codes
- https://bsd.dli.mt.gov/building-codes-permits/
- https://www.law.cornell.edu/regulations/montana/ARM-24-301-131
- https://www.law.cornell.edu/regulations/montana/Mont-Admin-r-24.301.401
- https://www.law.cornell.edu/regulations/montana/ARM-23-12-601
- https://mca.legmt.gov/bills/mca/title_0500/chapter_0600/part_0010/section_0020/0500-0600-0010-0020.html
- https://www.meltplan.com/buildingcodes/montana
Common questions
What building code does Montana use?
Montana uses 2021 IBC. It is administered by the Montana Department of Labor & Industry, Business Standards Division, Building & Commercial Measurements Bureau (Building Codes Program); fire code adopted by the State Fire Marshal, Montana Department of Justice.
Do cities in Montana amend the state code?
Local amendments are adopted by ordinance at the city or county level. Confirm with the building department that reviews your permit.
Check a plan set against Montana code
Knowing the adopted edition is the easy half. Architechtura reads your drawings, resolves which of these provisions actually apply to the project, and returns the corrections a plan checker would write up, each one cited to the section it came from.
Your first check is free, no card required.
Compiled from published state and municipal adoption ordinances. Local governments amend their codes on their own schedule, and a pending ordinance can change what applies to your permit. Confirm the governing edition with the building department before you submit. This page is reference information, not a code determination.