Barndominium Building Codes By State

There’s no special building code for barndominiums. A barndominium with living quarters is a house in the eyes of the law, so it’s built to the same residential code as any other home in your state, which in almost every state is based on the International Residential Code (IRC).

What changes from state to state is which edition of the code applies, whether the state enforces it everywhere or leaves it to counties, and what the code asks of a steel or post-frame building. The table below covers all 50 states, followed by what the code means for a barndominium in practice.

Do All States Have The Same Building Code?

No. Most states start from the same model codes, the IRC for homes and the International Energy Conservation Code (IECC) for energy, but each state adopts its own edition, adds amendments, and decides who enforces it. States fall into three groups:

• Statewide. One residential code applies everywhere, and a new home needs a permit and inspections wherever you build. Twenty states work this way, including Florida, New York, North Carolina, Pennsylvania and Virginia.
• Statewide, local option. The state has a code, but it only applies, or is only enforced, where a county or city chooses to adopt it, or localities may opt out. Many rural areas in these states have no residential inspections. Eighteen states work this way, including Alabama, Kentucky, Ohio, Oklahoma and Tennessee.
• Local only. There’s no statewide residential code at all. Counties and cities adopt their own, and many rural counties adopt none. Twelve states work this way, including Texas, Missouri, Colorado and Wyoming. A few of them, such as Delaware, Illinois and Nevada, still set a statewide energy code.

Even where no building code is enforced, a home still needs a septic permit, and usually an electrical inspection before the utility will connect power. Being outside a code area doesn’t mean being outside every rule.

Building Codes By State

Editions shown are the codes in force for new homes as of October 2026. “Local option” means the state code applies only where a county or city enforces it.

State	Residential Code	Enforcement	Energy Code	State Builder License	Official Source
Alabama	2015 IRC with Alabama amendments; new code applies Jan 1, 2027	Local option	2015 IECC with Alabama amendments	Over $10,000 (Home Builders Licensure Board)	Home Builders Licensure Board
Alaska	Local adoption	Local only	None statewide	Required, with residential endorsement	Alaska Housing Finance Corp. (BEES)
Arizona	Local adoption	Local only	None statewide	Required (Registrar of Contractors)	Registrar of Contractors
Arkansas	2021 Arkansas Residential Code	Local option	2014 Arkansas Energy Code (2009 IECC)	Over $2,000 (Contractors Licensing Board)	State Fire Marshal code list
California	2025 California Residential Code	Statewide	2025 California Energy Code (Title 24); solar required	Any job $1,000+ (CSLB)	Building Standards Commission
Colorado	Local adoption	Local only	Local; low-energy model code required on updates after July 1, 2026	None (local)	Colorado Energy Office
Connecticut	2021 IRC with Connecticut amendments	Statewide	2021 IECC with Connecticut amendments	Registration (new home contractors)	Office of the State Building Inspector
Delaware	Local adoption	Local only	2024 IECC with Delaware amendments	None (local)	DNREC energy codes
Florida	Florida Building Code, 8th ed. (9th ed. Dec 31, 2026)	Statewide	Florida Building Code, Energy Conservation	Required for any home built for others	Florida Building Commission
Georgia	2024 IRC with Georgia amendments	Local option	2015 IECC with Georgia amendments	Over $2,500 (State Licensing Board)	Dept. of Community Affairs
Hawaii	2018 IRC with Hawaii amendments	Statewide	2018 IECC with Hawaii amendments	Over $1,000 or any permitted job	Building Code Council
Idaho	2018 IRC with Idaho amendments	Local option	2018 IECC with Idaho amendments	Registration, over $2,000	Division of Occupational and Professional Licenses
Illinois	Local adoption	Local only	2024 IECC with Illinois amendments	None (local)	Capital Development Board
Indiana	2020 Indiana Residential Code (2018 IRC)	Local option	2018 IECC with Indiana amendments	None (local)	Fire Prevention and Building Safety Commission
Iowa	2024 IRC with Iowa amendments	Local option	2012 IECC with Iowa amendments	Registration (DIAL)	Dept. of Inspections, Appeals and Licensing
Kansas	Local adoption	Local only	None statewide (buyer disclosure only)	None (local)	Kansas Energy Office
Kentucky	2018 Kentucky Residential Code (2015 IRC)	Local option	2009 IECC with Kentucky amendments	None (local)	Dept. of Housing, Buildings and Construction
Louisiana	2021 IRC with Louisiana amendments	Statewide	2021 IECC with Louisiana amendments	Over $50,000 (State Licensing Board for Contractors)	Uniform Construction Code Council
Maine	2021 IRC with Maine amendments (MUBEC)	Local option	2021 IECC with Maine amendments	None	Maine building codes
Maryland	2021 IRC with Maryland amendments	Statewide	2021 IECC with Maryland amendments	Registration (Home Builder Registration Unit)	Building Codes Administration
Massachusetts	780 CMR 10th ed. (2021 IRC)	Statewide	2021 IECC; many towns add the Stretch or Specialized code	Construction Supervisor License	Board of Building Regulations and Standards
Michigan	2015 Michigan Residential Code (2021 edition blocked by court order)	Statewide	2015 IECC with Michigan amendments	Residential Builder license (LARA)	Bureau of Construction Codes
Minnesota	2020 Minnesota Residential Code (2018 IRC)	Local option	Minnesota Energy Code (2012 IECC)	Residential Building Contractor license	Dept. of Labor and Industry
Mississippi	2024 IRC; counties and cities may opt out	Local option	None statewide	Over $50,000 (State Board of Contractors)	—
Missouri	Local adoption	Local only	None statewide	None (local)	—
Montana	2024 IRC with Montana amendments	Local option	2024 IECC with Montana amendments	Registration (Dept. of Labor and Industry)	Building Codes Program
Nebraska	2018 IRC	Local option	2018 IECC	Registration (Dept. of Labor)	Nebraska energy codes
Nevada	Local adoption	Local only	2024 IECC	Required for any permitted work (State Contractors Board)	Governor’s Office of Energy
New Hampshire	2021 IRC with New Hampshire amendments	Local option	2018 IECC with New Hampshire amendments	None	State Fire Marshal building codes
New Jersey	2024 IRC/NJ edition	Statewide	2024 IECC with New Jersey amendments	New home builder registration	Division of Codes and Standards
New Mexico	2021 New Mexico Residential Building Code (2021 IRC)	Statewide	2021 New Mexico Residential Energy Code (2021 IECC)	Required (Construction Industries Division)	Construction Industries Division
New York	2025 Residential Code of NYS (2024 IRC)	Statewide	2025 NYS Energy Code (2024 IECC)	None (local)	Dept. of State codes
North Carolina	2018 NC Residential Code (2024 edition not yet in effect)	Statewide	2018 NC Energy Conservation Code	$40,000+ (Licensing Board for General Contractors)	Office of State Fire Marshal codes
North Dakota	2024 IRC with North Dakota amendments	Local option	2024 IECC, where adopted	Over $4,000 (Secretary of State)	Dept. of Commerce building code
Ohio	2019 Residential Code of Ohio (2018 IRC)	Local option	Residential Code of Ohio, Ch. 11	None (local)	Board of Building Standards
Oklahoma	2024 IRC with Oklahoma amendments	Local option	IRC Chapter 11 with Oklahoma amendments	None (trades only)	Uniform Building Code Commission
Oregon	2026 Oregon Residential Specialty Code (2024 IRC)	Statewide	Oregon residential energy provisions (ORSC Ch. 11)	Required (Construction Contractors Board)	Building Codes Division
Pennsylvania	2021 IRC with Pennsylvania amendments (UCC)	Statewide	2021 IECC with Pennsylvania amendments	None (registration covers remodeling only)	Uniform Construction Code
Rhode Island	2021 IRC with Rhode Island amendments (2024 IRC by Jan 1, 2027)	Statewide	2024 IECC with Rhode Island amendments	Registration (license from 2028)	Building Code Commission
South Carolina	2021 SC Residential Code (2024 edition Jan 1, 2027)	Statewide	2009 IECC	Over $5,000 (Residential Builders Commission)	Building Codes Council
South Dakota	Local adoption	Local only	None statewide	None (local)	State law, SDCL 11-10
Tennessee	2018 IRC with Tennessee amendments; local opt-out allowed	Local option	2018 IECC with Tennessee amendments	$25,000+ (Board for Licensing Contractors)	State Fire Marshal codes enforcement
Texas	Local adoption; cities enforce the IRC	Local only	2015 IECC (state minimum)	None (trades only)	State Energy Conservation Office
Utah	2021 IRC with Utah amendments	Statewide	2021 IECC with Utah amendments	Required (DOPL B100 or R100)	Utah Code Title 15A
Vermont	Local adoption	Local only	Vermont Residential Building Energy Standards	Registration, $10,000+	Residential Building Energy Standards
Virginia	2021 Virginia Residential Code	Statewide	2021 IECC with Virginia amendments	Class A, B or C license (DPOR)	Dept. of Housing and Community Development
Washington	2021 IRC with Washington amendments (2024 edition May 3, 2027)	Statewide	2021 Washington State Energy Code	Registration and $30,000 bond (L&I)	State Building Code Council
West Virginia	2018 IRC, where adopted	Local option	2015 IECC	$5,000+ (Contractor Licensing Board)	State Fire Marshal
Wisconsin	Uniform Dwelling Code	Statewide	Uniform Dwelling Code energy chapter (SPS 322)	Dwelling Contractor certification	Uniform Dwelling Code (SPS 320–325)
Wyoming	Local adoption	Local only	None statewide	None (local)	State Fire Marshal

Upcoming Code Changes

Several states are mid-update, so check the effective date against your permit date:

• Florida: the 9th edition of the Florida Building Code takes effect December 31, 2026.
• South Carolina: the 2024 South Carolina Residential Code takes effect January 1, 2027.
• Rhode Island: state law requires the 2024 IRC to take effect by January 1, 2027.
• Alabama: a new residential code from the Home Builders Licensure Board applies from January 1, 2027.
• Oregon: the 2026 Oregon Residential Specialty Code becomes mandatory April 1, 2027.
• Washington: the 2024 codes take effect May 3, 2027.
• North Carolina: the 2024 code is adopted but has no start date yet; May 1, 2027 is the earliest possible.
• Michigan: the 2021 code remains blocked by a court order, so the 2015 code still applies.

Code editions change on each state’s own schedule, often every three years. Before you finalize plans, confirm the edition and any local amendments with the building department for your county or city.

What The Code Means For A Barndominium

The residential code was written with wood-framed houses in mind. A barndominium meets the same code, but a few requirements land differently on a steel or post-frame building.

Engineered Frames And Stamped Drawings

The IRC’s prescriptive rules cover conventional wood framing and light-gauge steel framing within set limits. A red iron frame, a wide clear span, or a post-frame building outside those limits has to be designed by an engineer instead, which the IRC allows under Section R301.1.3. In practice, the building department will ask for drawings stamped by an engineer licensed in your state, and a quality steel kit or post-frame package should include them. Ask before you buy whether the price covers stamped drawings for your address.

Wind, Snow And Seismic Loads

Every jurisdiction sets its own design criteria, including wind speed, ground snow load, seismic category and frost depth, in a table under IRC Section R301.2. The frame has to be engineered for those numbers at your site, which is why a steel building quote without your address is only an estimate.

Footings And Frost Depth

Footings must sit at least 12 inches below undisturbed ground, and below the local frost line, under IRC Section R403.1.4. That’s a few inches in the Deep South and 42 to 48 inches or more in the northern states. A frost-protected shallow foundation, insulated to keep the ground under it from freezing, is an approved alternative in most states under Section R403.3. The building department sets the frost depth for your county.

Energy Code And Insulation

The energy code applies to a barndominium like any house. Steel conducts heat far faster than wood, so a metal-framed wall needs more insulation to reach the same result, usually continuous insulation outside the frame or closed-cell spray foam rather than batts between steel girts. In states with a current energy code, plan the insulation before you order the building, because it can change the frame and trim details.

The Shop And The House

If the shop is attached to the living space and used to park vehicles, the code treats it like an attached garage. That generally means half-inch drywall on the shop side of the shared wall, 5/8-inch Type X drywall on the ceiling where living space sits above, and a solid or 20-minute fire-rated door between the two, under IRC Sections R302.5.1 and R302.6. Our garage barndominium guide covers the details.

Life-Safety Basics

Every bedroom, and any basement, needs an emergency escape window or door (IRC Section R310). Smoke alarms are required in each bedroom, outside sleeping areas and on every level, and carbon monoxide alarms are required where the home has fuel-burning appliances or an attached garage (IRC Sections R314 and R315). These are easy to miss in a large open barndominium plan, so check them on the drawings.

Farm And Agricultural Exemptions Don’t Cover Homes

Many states exempt farm buildings from the building code, which leads to a common question: can a barndominium on farmland be built as an agricultural building? In nearly every state, no. Farm exemptions cover barns, equipment sheds and livestock buildings, and they stop applying the moment the building is used as a home. Kentucky is the notable exception: a farm dwelling outside city limits is excluded from the state building code, though electrical rules still apply.

Building a home as a farm building to avoid inspections can also make it hard to insure, finance or sell later, because lenders and appraisers expect a permitted residence.

Building Codes, Permits And Your Build

The code sets how the home must be built. Permits are how your county or city checks it, and the rules for which permits you need, and when, vary as much as the codes do. For state-specific rules on licensing, septic and local hazards, start with your state’s barndominium guide.

Barndominium Building Code FAQ

Start With Plans Built For Code

Whatever your state’s code, it starts with a good set of plans. A complete plan set gives your engineer, builder and building department the same drawings to work from.

Browse barndominium floor plans →

Shop stock plans with prices →

This page is for general information. Building codes, editions and local amendments change, so confirm the requirements for your parcel with your city or county building department before you build.