Idaho

Idaho Permit Guide for Metal Carports, Garages and Barns

In most of Idaho, a metal carport or garage needs a building permit from the city or county where it will sit, and the state code only lets small one-story buildings skip one. Idaho builds on the 2018 International Residential Code, but each city and county that runs a building program adopts it by ordinance and issues its own permits. So the real answer to any Idaho carport permit question comes from your local building or planning office. Size, enclosed walls and whether the property is a farm, home or business all change the answer. Start with a call to the office that covers your address before you order.

Building code in effect

Idaho's homes and small buildings follow the Idaho Residential Code (2020 Edition), which is the 2018 International Residential Code (Parts I, II, III and IX) with state amendments. Larger and commercial buildings follow the 2018 International Building Code with amendments. The "2020 Edition" label refers to the legislative session that approved the amendments, not a newer code book. A rule to move to the 2024 codes did not pass the House in the 2026 session, so the 2018 editions are still the ones in effect. Under Idaho Code 39-4116, local governments that issue building permits must adopt these codes by ordinance, and they can amend them only if the change gives at least an equal level of protection.

Who issues permits

Building permits for a carport, garage or barn come from the city or county building department that runs a code enforcement program for your address. Idaho Code 39-4111 says work in a local jurisdiction that enforces building codes needs a permit under that local ordinance. The Idaho Division of Occupational and Professional Licenses (DOPL) handles state-owned buildings, factory-built structures and manufactured home installs, and it issues manufactured home permits where no approved local program exists. Zoning is a separate check: setbacks, lot coverage and land use rules are set by the city or county planning and zoning office, and a county can still require a permit for road setbacks even when the building itself is code-exempt.

County permit guides

County guides are coming soon.

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When you need a permit

Small sheds and carports: Very small one-story detached buildings can be exempt from a building permit under the residential code's exempt-work list. Ask your building department what size cutoff it uses, and expect a zoning or setback check either way.
Larger garages and carports: Anything over the exemption size needs a building permit from the local building department, along with plans that show the frame, anchoring and design loads.
Enclosing a carport: Adding walls to an open carport changes how the code treats it, so check with the building office before you add side panels or doors.
Commercial property: Buildings for a business fall under the 2018 International Building Code with Idaho amendments, which usually means a fuller plan review.
Agricultural buildings: Barns, equipment storage and livestock shelters on farms are exempt from the building codes under Idaho Code 39-4116, but a county may still issue a setback permit.

Farm buildings

Idaho Code 39-4116(5) says local governments shall exempt agricultural buildings from the building codes in the Idaho Building Code Act. The law counts livestock shelters, poultry buildings, barns, equipment storage, horticultural structures, grain silos and stables as agricultural buildings. It does not cover a place where people live, sleep or cook, a place where farm products are processed or packaged, or a building used by the public. Counties cannot narrow the exemption with size limits or sprinkler rules, but they can issue a permit to check road setbacks and utility easements, at a cost no higher than the county's actual cost. Many counties ask for an ag exempt form or affidavit, so ask yours what it needs.

Wind and snow

Snow is the big structural question in Idaho. Mountain valleys, the central Idaho high country and the northern panhandle can carry heavy ground snow loads, and the number can change a lot between nearby sites with different elevations. DOPL's guidance says snow loads follow the International Building Code and points to location-based hazard lookups, but the local building office sets the design values you must meet. Wind also matters on the open Snake River Plain. Ask your city or county office what ground snow load and wind speed your building must be engineered for before you pick a building. 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

Call your county or city building office and ask three things: is a building permit needed at this size, what ground snow load applies at my address, and do you need stamped engineered drawings.
If it is a farm building, ask whether the county wants an ag exempt affidavit or a setback permit, and get that paperwork done before delivery.
Check subdivision covenants or HOA rules, since many Idaho subdivisions limit metal buildings, colors or height even when the county allows them.
Have the site level and the anchoring plan decided ahead of time, whether that is a concrete slab, piers or ground anchors, so it matches the approved plans.

Common questions

Do I need a permit for a carport in Idaho?
Usually yes. Only small one-story detached structures can skip a building permit, and most carports are bigger than that cutoff. Your city or county issues the permit and may also check zoning setbacks.

Do I need a permit for a metal garage in Idaho?
Yes in most places. An Idaho metal garage permit is a standard building permit from your local building department, and the plans need to show the building can handle the local snow and wind loads. Areas without a local building program may handle it differently, so call first.

Are farm buildings exempt in Idaho?
Yes. Idaho Code 39-4116 requires local governments to exempt agricultural buildings such as barns, equipment storage and livestock shelters from the building codes. Counties can still require a permit to check road setbacks and utility easements. A building where people live or where the public comes in does not qualify.

Which building code does Idaho use?
Idaho uses the 2018 International Residential Code with state amendments (called the Idaho Residential Code, 2020 Edition) and the 2018 International Building Code with amendments. A move to the 2024 codes did not pass in the 2026 legislative session.

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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