Under the model residential building code used in most of the United States, the biggest shed you can build without a permit is a one-story detached structure of 200 square feet or less. That ceiling comes from the International Residential Code, and it is only a starting point: your city or county may have adopted a lower limit, added height or foundation conditions, or carved out exceptions that pull your project back into the permit process even when the footprint is small.1International Code Council. 2021 International Building Code
Where the 200 Square Foot Number Comes From
Section R105.2 of the International Residential Code lists work exempt from a building permit. The first item on that list is one-story detached accessory structures with a floor area of 200 square feet or less. That is the origin of the number repeated everywhere.
Local governments adopt the IRC and then amend it. Some keep the full 200-square-foot exemption. Others lower the cap to 120 or 100 square feet. A few add height limits, restrict foundation types, or exclude any structure with plumbing. So 200 is the ceiling built into the model code, but the number that actually governs your yard depends on what your jurisdiction adopted.
Watch the phrasing, too. An exemption written as “200 square feet or less” includes a 10-by-20 shed; one written as “less than 200 square feet” does not. That one-word difference catches people out when they design right at the limit.
What Can Push You Back Into the Permit Column
How the Footprint Is Measured
Some jurisdictions measure the floor area from exterior wall dimensions. Others use the roof’s projected area, which includes overhangs and can add meaningful square footage if the eaves are wide. If your design sits near the size limit, confirm which method applies before you cut lumber.
Height
Many jurisdictions cap the height of permit-exempt accessory structures. Twelve feet from grade to roof peak is common. Some allow up to 15 feet; others set the limit as low as 8 or 10 feet. A shed that is small enough on the ground but too tall at the ridge still needs a permit.
Foundation
How the shed meets the ground often decides the permit question. A shed on gravel, concrete blocks, or wood skids is generally treated as movable and stays within the exemption. A poured slab or poured footings signal permanence and can trigger a permit requirement even for a structure under the size cap. Local codes sometimes name which foundation types are acceptable for exempt sheds, particularly in areas with problem soils or freeze-thaw cycles.
Utilities
Running electricity, plumbing, or gas to a shed almost always requires its own permit, regardless of the shed’s size. Electrical work triggers an electrical permit and inspection. A sink, toilet, or any fixture triggers a plumbing permit. These are separate tracks from the building permit, so a shed that qualifies for the size exemption loses that advantage the moment it gets wired or plumbed.
Small off-grid solar is a gray area. Some jurisdictions exempt low-wattage portable kits with no grid connection; others require electrical permits for any permanent wiring, inverter, or panel installation. Call the building department before assuming off-grid gets you out of it.
Rules That Still Apply Even When No Permit Is Required
Skipping the building permit does not mean skipping everything else. Zoning rules apply to every structure on your property, permitted or not, and a shed that falls under the size exemption can still trigger enforcement action.
Setbacks
Setbacks dictate the minimum distance a structure must sit from property lines, streets, and other buildings. Side-yard setbacks of three to seven feet are common. Rear-yard setbacks can run from five to twenty feet. Easements add another layer: if a utility easement runs along the back fence, a shed placed in that easement can be ordered removed even if it is a 64-square-foot box that needed no permit. Your property survey or plot plan, usually included in your closing paperwork, shows the boundaries and recorded easements.
Lot Coverage
Zoning ordinances typically cap the percentage of a lot that can be covered by buildings and impervious surfaces. That cap includes the house, driveway, patio, garage, and any shed. On a small urban lot already near the limit, a modest shed may push coverage over the line even though no permit was required for the shed itself.
Homeowners Associations
HOA approval and municipal permits are separate systems; satisfying one does not excuse you from the other. If you live under a set of Covenants, Conditions, and Restrictions, the architectural review committee likely has to approve any outdoor structure before you build, and the HOA rules on size, height, placement, materials, and color are often stricter than the city code. Ignoring the HOA can bring daily fines, mandatory removal at your expense, liens, or lawsuits. Review itself commonly takes 30 to 60 days.
Situations That Erase the Exemption Entirely
Flood Zones
If your property sits in a Special Flood Hazard Area, the standard size-based exemption likely does not apply. The National Flood Insurance Program requires local jurisdictions to permit all development in those areas, and “development” under federal regulations covers any man-made change to real estate, including construction of structures of any size.2FEMA. Permit for Floodplain Development3eCFR. Title 44 CFR Section 59.1 Even where a small shed in a flood zone escapes elevation requirements, it typically still needs a floodplain development permit and has to meet conditions on anchoring, flood-resistant materials, and venting. You can check your flood status at msc.fema.gov.
Historic Districts and Environmental Overlays
Properties in designated historic districts or environmental overlay zones face additional review that can override the standard exemption. A historic district commission may require approval for any new construction visible from the street, regardless of size. Overlays near wetlands, shorelines, or protected habitats add their own permitting layers. In those zones, the size-based exemption is a starting point, not the final answer.
How to Confirm the Limit That Applies to You
Start with your city or county website and look for the building department, development services, or planning and zoning office. Search for “accessory structure” or “shed permit.” Many jurisdictions publish a handout or FAQ that lays out the exact size, height, and foundation limits for permit-exempt structures, and those summaries are easier to use than the underlying code.
If the website does not answer the question, call. When you do, ask specifically about:
- The maximum floor area and roof height for permit-exempt sheds
- Whether floor area is measured by exterior walls or by roof projection
- Setback distances from property lines and existing structures
- Whether a permanent foundation triggers a permit on its own
- Whether your property is in a Special Flood Hazard Area
Write down the name of the person you spoke with and the date. If a dispute comes up later, that note is worth having.
What It Costs to Guess Wrong
If code enforcement finds an unpermitted structure that should have been permitted, the first step is usually a stop-work order freezing construction until the violation is resolved. Resolving it means applying for a retroactive permit, and most jurisdictions charge two to three times the standard fee for after-the-fact applications. The inspection is also more invasive, because the inspector cannot see what is behind finished surfaces; you may have to open walls or floors so framing, wiring, and connections can be examined.
If the structure does not meet code, you have to bring it into compliance before the retroactive permit can issue, which can mean significant rework. In serious cases, where the shed violates zoning or poses a safety risk, the city can order complete demolition at your expense. Fines run from a few hundred to several thousand dollars depending on the jurisdiction and the severity of the violation.
The quiet cost shows up at resale. Appraisers generally cannot include the value of unpermitted improvements, and lenders, especially on FHA and VA loans, are cautious about properties with unpermitted work. A shed that cost a few thousand dollars to build can turn into a five-figure problem when the house goes on the market.