Montana

Montana Permit Guide for Metal Carports, Garages and Barns

In most of Montana, a metal carport or garage for your own use at home doesn't need a state building permit, because state law exempts private garages and storage buildings used only by the owner. The catch is that this exemption covers only areas outside a certified local program. If you live in a certified city, or in a county that runs its own program such as Missoula County or Butte-Silver Bow, that local office decides what a Montana carport permit requires. A building used for a business is a different story, since the state treats it as a commercial building that needs plans and a permit. Start by calling your city or county, then check with the state Building Codes Bureau if you're outside a certified area.

Building code in effect

Montana adopts its building codes by rule under ARM Title 24, Chapter 301. According to the Department of Labor and Industry's current codes page, the state now uses the 2024 International Building Code and the 2024 International Residential Code, both effective September 26, 2026, along with the 2023 National Electrical Code. Earlier projects were reviewed under the 2021 editions. Certified cities and counties enforce these same codes inside their own boundaries. Under MCA 50-60-102, the state code doesn't apply to homes with fewer than five units, farm or ranch buildings, or private owner-use garages and storage buildings unless a local government adopts an ordinance or resolution that brings them under the code.

Who issues permits

Montana has 41 certified local building programs (36 cities and 5 counties). The certified counties are Missoula, Butte-Silver Bow, Richland (everywhere except Sidney) and Pondera and Toole (commercial buildings only). Inside those areas, the local building department issues permits. All other areas fall under the state Building Codes Bureau in Helena, which handles commercial buildings and anything else the state code covers. Zoning is a separate check. Many counties and towns have their own zoning, land use or floodplain rules even where no building permit is needed, so ask about setbacks and placement too.

County permit guides

County guides are coming soon.

Don't see your county? Call 919-725-8176 and we'll help you find the right office.

When you need a permit

Private garages and storage: Outside certified areas, the state exempts private garages and storage buildings used only by the owner. A building used to store or repair vehicles for a business, or to hold business equipment or products, doesn't qualify.
Homes under five units: Houses and residential buildings with fewer than five units (not serving transient guests) are exempt from state permits, and so are structures attached to them, unless your local government has adopted the code for them.
Certified cities and counties: If your city or county is on the state's certified list, its own permit rules apply. Under MCA 50-60-102, a local government can make the code apply to homes, garages and storage buildings, so ask before you assume an exemption.
Commercial property: A metal building for a business needs a state building permit outside certified areas. You submit plans with a Building Permit/Plan Review Application, and the plan review fee is 35 percent of the permit fee.
Wiring the building: Electrical work needs a permit even when the building doesn't. Homeowners can wire their own garage under a state homeowner electrical permit with state inspection; other work needs a licensed electrical contractor.

Farm buildings

Under MCA 50-60-102, the state building code doesn't apply to any farm or ranch building, and the Building Codes Bureau says these buildings are exempt from the state permit process. ARM 24.301.146 defines a farm or ranch building as one located on and used with an agricultural use of land that totals 160 or more contiguous acres under one ownership, or that is classified as agricultural under Title 15, chapter 7, part 2, MCA. A barn on a smaller parcel without agricultural classification may not qualify. Local requirements can still apply, and any wiring still needs an electrical permit.

Wind and snow

Snow is the big structural question in Montana. Loads change a lot between the plains and the mountain valleys, and the state's rules say snow loads are set by the building official. For buildings under state jurisdiction, design snow loads come from ASCE 7-22 (the ASCE 7 Hazard Tool gives values by location), with a minimum design roof snow load of 30 psf. Wind along the Rocky Mountain Front and across the open plains matters too. Ask your local office or the state bureau what ground snow load and wind speed your building must be engineered for before you order. Our partnered manufacturers offer certified buildings rated for 140 MPH wind and 35 PSF snow load, and higher ratings can be quoted where required.

Before you order

Find out whether your address sits inside a certified city or county. The state's certified list is short, and if your town isn't on it, the state rules apply.
If the building will ever be used for a business, ranch hand housing or anything beyond your own storage, ask the state bureau whether it becomes a commercial building needing plans.
Ask for the design snow load at your exact site. Footings also need to go below frost depth, which the state sets at three feet minimum for single-story metal frame buildings outside certified areas.
Check for zoning, floodplain, subdivision covenants or HOA rules even when no building permit applies, and plan ahead for a homeowner electrical permit if you'll add lights or outlets.

Common questions

Do I need a permit for a carport in Montana?
Outside certified cities and counties, a carport for your own private use is exempt from state building permits. Inside a certified area like Missoula County or a certified city, check with that office, since it sets its own permit rules.

Do I need a permit for a metal garage in Montana?
A private garage that only holds your own vehicles is exempt from state building permits outside certified areas. If it serves a business, it needs a state permit, and any electrical work needs an electrical permit either way.

Are farm buildings exempt in Montana?
Yes. MCA 50-60-102 exempts farm and ranch buildings from the state building code. State rules define them as buildings used in agriculture on 160 or more contiguous acres under one owner, or on land classified as agricultural for tax purposes.

Who do I call about a Montana metal building permit?
Start with your city, town or county. If they aren't on the certified list, contact the state Building Codes Bureau in Helena at (406) 841-2056.

Sources

Permit rules change. Always confirm with your local permit office before you build.

Looking at buildings? See our metal carports, metal garages and metal buildings.

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