Illinois

Illinois Permit Guide for Metal Carports, Garages and Barns

Whether you need a carport permit in Illinois depends on your city, village or county, because there is no one statewide permit office for a carport or garage. Cities, villages and counties each decide if they will adopt a building code, and plenty of rural counties have zoning but no building inspections at all. That means the rules can change when you cross a city limit or a county line. Farm buildings also get a real break from county zoning under state law. Call the city or county where the building will sit before you order.

Building code in effect

Illinois leaves building codes to local government. The Capital Development Board (CDB) says plainly that a municipality or county is not required to adopt building codes, and places that don't are treated as non-building code jurisdictions. Public Act 103-0510 amended the Capital Development Board Act to set statewide baseline building codes effective January 1, 2025. Under that change, any city or county that does adopt a code must base it on model codes and cover the structural design of new commercial, existing commercial and residential buildings. CDB says the adopted code must meet the minimum structural requirements of the International Residential Code (IRC), and the most common approach is adopting the IBC, IEBC and IRC. Local governments must report new or amended codes to CDB at least 30 days before they take effect, and CDB lists local codes in its Illinois Code Directory.

Who issues permits

Inside a city or village, the municipal building department issues permits under whatever code that town has adopted. In unincorporated areas, it depends on the county. Some counties run a full building and zoning department, while others only issue zoning or placement permits and do no building inspections. The zoning permit is often a separate step from any building permit, and setbacks come from the county or city zoning ordinance. If the property is in a flood zone or uses a private septic system, the county health department or floodplain office may need to sign off 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

No code, no building permit: If your city or county has not adopted a building code, there may be no building permit at all. You may still need a zoning permit for placement and setbacks.
Local size limits: Many Illinois towns and counties that do have codes exempt small sheds under a set square footage, but the cutoff is set locally. Ask before you assume your carport or garage qualifies.
Farm buildings: State law bars counties from requiring zoning permits for buildings used for agriculture on farm land in unincorporated areas, though setback lines can still apply.
Commercial use: In counties without a building code, CDB says new commercial buildings generally need an Illinois-licensed design professional and a certification of inspection under the Capital Development Board Act.
Inside city limits: The county farm exemption does not carry into a city or village. Municipal codes apply to garages, carports and shops inside town.

Farm buildings

Illinois county zoning law includes a strong agricultural exemption. Under 55 ILCS 5/5-12001 of the Counties Code, a county's zoning powers cannot be used to impose regulations, eliminate uses, buildings or structures, or require permits for land used for agricultural purposes, or for buildings and structures used for agricultural purposes on that land. The same section says agricultural buildings can still be required to meet building or setback lines. This applies in unincorporated county areas. It does not cover property inside a city or village, and a building used for a business, a home or anything other than farming may not qualify. Ask the county zoning office what proof of farm use they want to see.

Wind and snow

Illinois is long from north to south, and that matters for snow. The northern counties around Chicago and Rockford see heavier ground snow loads than the southern tip near Cairo. The whole state sits in tornado and severe thunderstorm country, and strong straight-line winds hit open farm ground every year. Since codes are set locally, your city or county decides what wind speed and snow load your building has to be engineered for, so ask them 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 first if your lot is inside a city or village or in unincorporated county. That decides who you call.
Ask the county if they have a building code or only zoning. Some Illinois counties only check placement and setbacks.
If you're claiming the farm exemption, ask the county what paperwork they want to see showing the land and building are used for agriculture.
Get the required wind and snow numbers from the local office in writing, then order certified drawings to match.

Common questions

Do I need a permit for a carport in Illinois?
It depends on where you live. Illinois has no single statewide permit office, and cities and counties decide whether to adopt a building code. Inside most towns you will need a permit. In some rural counties you may only need a zoning or placement permit. Call the local office first.

Do I need a permit for a metal garage in Illinois?
Usually yes if your city or county has adopted a building code, since a garage is a bigger structure. Where a jurisdiction has a code, Illinois law now requires it to meet the structural requirements of the International Residential Code. In counties with no building code, you will likely still need a zoning permit for setbacks.

Are farm buildings exempt?
In unincorporated county areas, mostly yes. Under 55 ILCS 5/5-12001, counties cannot require zoning permits for buildings used for agricultural purposes on farm land. They can still require you to meet setback lines. The exemption does not apply inside city or village limits.

Sources

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

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