New Hampshire

New Hampshire Permit Guide for Metal Carports, Garages and Barns

Whether you need a carport permit in New Hampshire depends on your town, even though one building code covers the whole state and every building is supposed to meet it. What changes from town to town is who checks your work. Many cities and towns have a building inspector and issue permits, while some small towns have no local enforcement at all. Zoning and setbacks are always local, so the town office is where you start for a carport, garage or barn.

Building code in effect

The New Hampshire State Building Code is set by RSA 155-A and is based on the 2021 International Residential Code and 2021 International Building Code, with state amendments, plus the 2023 National Electrical Code. The update was made by HB 1059 (2024), which took effect retroactive to July 1, 2024. Under RSA 155-A:2, all buildings and structures built in New Hampshire must comply with the state building code and state fire code, and a town may adopt rules that are stricter than the state code but not weaker.

Who issues permits

Building permits are issued by the city, town or village district (RSA 155-A:2). Towns with a building inspector or another enforcement setup review plans and do inspections. In a town with no local enforcement, the code still applies, and the State Fire Marshal may enforce it if the town asks in writing. In those towns, contractors must notify the State Fire Marshal before building, except for one- and two-family homes. Zoning permits and setbacks come from the local zoning ordinance and are separate from the building permit.

County permit guides

When you need a permit

Small sheds: The 2021 IRC, which New Hampshire adopted, exempts a one-story detached accessory building of up to 200 square feet from a building permit. Your town can be stricter, and zoning setbacks still apply even when no building permit is needed.
Garages, barns and carports: Anything over that size needs a building permit in towns that enforce the code. Expect to show the foundation, framing or engineered drawings, and where it sits on the lot.
Towns with no building inspector: The state code still applies to your building. There may be no local building permit to pull, but zoning rules, setbacks and any town permits still apply, so ask the selectmen's office.
Electrical work: Wiring a garage or barn falls under the 2023 National Electrical Code as adopted by the state. Ask your town whether it wants a separate electrical permit for the work.

Farm buildings

New Hampshire does not give farm buildings a blanket exemption from the state building code. The state's 2021 amendments adopt IBC Appendix C, which sets specific rules for Group U agricultural buildings. On the zoning side, farmers get more room. RSA 674:32-a treats agriculture as allowed when a zoning ordinance is silent, and RSA 674:32-c protects growing crops in every district. RSA 674:32-c also says new or expanded farm operations still have to meet general building and site rules like setbacks and dimensional standards, but the local board can grant a waiver when a rule would be unreasonable for the farm use.

Wind and snow

Winter is the big design factor in New Hampshire. The White Mountains and the North Country see deep snow, and ground snow loads rise quickly with elevation, so two lots in the same town can have different roof loads. The Seacoast deals more with nor'easters and coastal wind. Ask your local building office for the ground snow load and design wind speed at your exact address 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

Ask your town if it has a building inspector. That tells you whether you pull a building permit locally or only deal with zoning.
Get the ground snow load for your site from the town. In hill towns it can change a lot from one road to the next.
If you farm, ask the planning or zoning board about a waiver under RSA 674:32-c before you assume setbacks will block your barn.
Check zoning setbacks even for a shed under 200 square feet. The size exemption only covers the building permit.

Common questions

Do I need a permit for a carport in New Hampshire?
In most towns with a building inspector, yes, unless it is a small one-story structure that fits the 200 square foot exemption in the 2021 IRC and your town has not made that stricter. Zoning setbacks apply either way.

Do I need a permit for a metal garage in New Hampshire?
Yes in towns that enforce the state building code, which is based on the 2021 IRC and IBC. If your town has no building inspector, the code still applies to the building, so it still needs to be built to code and meet zoning.

Are farm buildings exempt?
Not from the state building code. New Hampshire adopted IBC Appendix C for agricultural buildings. Zoning is more flexible: under RSA 674:32-c a local board can waive setbacks and similar rules when they would be unreasonable for a farm use.

Sources

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

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