Do I Need a Permit for a Shed? Size Limits by State
Applies to detached sheds at one- and two-family homes. Your city or county building department sets the final rule and can be stricter than its state. This guide explains the rules; it does not confirm that your shed is exempt.
The short answer most people have heard is right for the model code: the International Residential Code (IRC) lets you build a one-story detached shed up to 200 square feet without a building permit. The International Building Code (IBC), which covers commercial and other non-residential property, uses 120 square feet. But neither number is a national law. They only apply where a state or city adopts them as written, and many don't.
Verified state and city limits run from 50 square feet (the City of St. Louis) to 1,000 square feet (Pennsylvania), with some cities, like Tucson, requiring a permit for every shed. Several states add a height limit the model code doesn't have, and New York leaves the decision to each town.
Even when a shed is exempt from a building permit, it is not exempt from zoning, setbacks, electrical permits, flood rules or your HOA, and it still has to be built to code. This guide covers the model rule, every state limit we could confirm from the actual code text, common city limits, and a checklist to run before you buy or pour a slab.
A poured slab can change whether your shed is exempt, so confirm the permit rule before you order concrete for the pad. Free, no signup.
The Model Code: 200 Square Feet (IRC) or 120 (IBC)
The current 2024 IRC exempts "one-story detached accessory structures, provided that the floor area does not exceed 200 square feet," other than storm shelters. That wording is unchanged from the 2021 edition, and the 2024 IRC did not renumber it. The IBC version is narrower in two ways: it caps the floor area at 120 square feet and limits the use to "tool and storage sheds, playhouses and similar uses." Sheds at houses normally fall under the IRC, but some states and cities apply the 120-square-foot figure to homes too. Neither model code sets a height limit beyond "one-story," and neither says anything about electricity; those conditions come from state and local amendments.
| Code | Section | Shed size exempt from a permit |
|---|---|---|
| 2024 / 2021 IRC (houses) | R105.2, item 1 | One story, detached, floor area 200 sq ft or less (not a storm shelter) |
| 2024 IBC (non-residential) | [A]105.2, item 1 | One story, detached tool/storage shed or playhouse, 120 sq ft or less |
Statewide Shed Limits We Verified
These are the states where we read the statewide rule in the adopted code or regulation itself. Many other states adopt the IRC and are probably at 200 square feet, but we could not confirm their text, so they are not listed with a number. In states without a statewide residential code (including Arizona, Colorado, Illinois, Kansas, Missouri and Texas), every city and county sets its own rule. Even where a statewide number exists, local zoning can still require a permit or registration.
| State | Shed exempt from a building permit | Source |
|---|---|---|
| California | 120 sq ft (sheds may still have to meet wildfire-zone rules in Section 710A) | CRC R105.2, item 1 |
| Connecticut | 200 sq ft, tool/storage sheds and playhouses | CT State Building Code, IRC R105.2 as amended |
| Louisiana | Up to 500 sq ft footprint, detached: parishes and most municipalities may not enforce the state code on it. Does not apply in high-wind areas (100 mph+ in hurricane-prone regions, 110 mph+ elsewhere), and cities over 45,000 people may still enforce | La. R.S. 40:1730.30 |
| Massachusetts | 200 sq ft | 780 CMR 51 R105.2, item 1 |
| Minnesota | 200 sq ft | Minn. R. 1300.0120, subp. 4 |
| New Jersey | 200 sq ft and 10 ft tall or less, no water, gas, oil or sewer connection | N.J.A.C. 5:23-2.14(b)(8) |
| New York | Up to 144 sq ft only where the town or city has chosen to exempt sheds | 19 NYCRR 1203.3(a)(1)(i) |
| North Carolina | Permit required if any dimension is over 12 ft (so roughly 12 × 12 ft or smaller is exempt) | NC Residential Code R101.2.1, as quoted by county building departments |
| Ohio | 200 sq ft | Residential Code of Ohio 102.10 |
| Oregon | 200 sq ft and 15 ft tall (to average roof height); 400 sq ft on lots of 2+ acres if 20 ft from property lines | Oregon Residential Specialty Code R105.2 |
| Pennsylvania | Under 1,000 sq ft, accessory to a single-family home: excluded from the state code (towns may still regulate by ordinance) | 34 Pa. Code §403.1(b)(3) |
| Rhode Island | 200 sq ft | RI State Building Code (510-RICR-00-00-2) R105.2 |
| Virginia | 256 sq ft building area (not a Group F-1 or H occupancy) | USBC 108.2 (13VAC5-63-80) |
City Limits Vary Even More
Where there is no statewide code, or where cities amend it, the number changes from one city line to the next. These are limits we read on each city's own code or permit page. Several popular shed-permit articles get them wrong: Houston is often listed at 200 square feet (it is 120), San Antonio at 200 (it is 300), and Tucson as exempt under 200 (every shed there needs a permit).
| City | Shed exempt from a building permit | Source |
|---|---|---|
| St. Louis, MO (city) | 50 sq ft or less, if setbacks are met | City permit criteria page |
| Houston, TX | 120 sq ft | Houston Permitting Center |
| Chicago, IL | 150 sq ft, 15 ft tall or less, no plumbing | Municipal Code §14A-4-402.1 |
| Phoenix, AZ | 200 sq ft total of all exempt sheds; utilities need their own permit | Phoenix building code 105.2.1 |
| Kansas City, MO | Under 200 sq ft | City code questions page |
| Colorado Springs area (Pikes Peak RBD) | 200 sq ft and supported directly on grade | PPRBD 105.2 |
| San Antonio, TX | 300 sq ft, plus city setback rules | City no-permit-required page |
| Tucson, AZ | No exemption: every shed needs a permit (site plan only under 200 sq ft with no utilities) | City permit exemptions page |
Exempt From a Permit Is Not Exempt From the Code
The IRC is explicit: an exemption from the permit "shall not be deemed to grant authorization for any work to be done in any manner in violation of the provisions of this code or any other laws or ordinances of this jurisdiction." An exempt shed still has to be built to code; Minnesota's building officials point out, for example, that a shed wall less than 5 feet from the property line must be one-hour fire-resistance rated. And the permit exemption covers the building permit only. Zoning setbacks, lot coverage and the number of accessory buildings are set by local zoning, which often needs its own permit or registration. Electrical, plumbing or gas work in the shed needs its own trade permit (New Jersey's rule says so directly). Exemptions are commonly void in flood zones, wetland and other critical areas, and historic districts. HOA covenants are private rules and can be stricter than any of these.
How "Floor Area" Is Measured
The model code doesn't define how to measure a shed's floor area, and jurisdictions differ: some measure outside wall to outside wall, some use "gross floor area" or "building area," and a few use the projected roof area, which counts the overhangs. The safe approach is to measure the outside footprint, and to measure to the roof edge if your city uses roof area. If you're within a few square feet of the limit, assume you need a permit, or get the measuring rule from the building department first. Note that some limits are "not greater than" a number and some are "less than" it, so a shed exactly at the limit may or may not qualify.
Foundations, Slabs and Pre-Built Sheds
A poured slab or permanent foundation can change the answer. The Pikes Peak Regional Building Department, for example, exempts sheds only when they are "supported directly on grade." Ask before you pour concrete. Delivered, pre-built sheds follow the same size limits as site-built ones, and you should confirm setbacks, delivery access, any required location permit or registration, and anchoring rules before the truck arrives.
Standards & Citations
| Standard | Code / Section | Requirement |
|---|---|---|
| IRC Permit Exemption for Detached Accessory Structures | 2024 IRC R105.2, item 1 | One story, detached, floor area 200 sq ft or less, not a storm shelter. Unchanged from the 2021 IRC. |
| IBC Permit Exemption for Sheds | 2024 IBC [A]105.2, item 1 | One-story detached tool and storage sheds, playhouses and similar uses, 120 sq ft or less. |
| Certificates of Occupancy for Exempt Work | 2024 IRC R110.1, Exception 1 | Certificates of occupancy are not required for work exempt from permits under R105.2. |
Apply These Requirements
Open a calculator to run this guide’s requirements against your own project.
Concrete Calculator
A poured slab can change whether your shed is exempt, so confirm the permit rule before you order concrete for the pad.
Gravel Calculator
A gravel pad keeps a shed "supported directly on grade," the condition some jurisdictions attach to the exemption.
T1-11 Siding Calculator
Sizing T1-11 siding for a shed? Check the size limit first: a few feet of extra length can push it over the exemption.
Stud Wall Framing Calculator
Exempt sheds still have to be built to code, so frame them the way a permitted structure would be framed.
Get Accurate Pricing From Local Contractors
Compare real pricing from licensed professionals in your area based on your estimate.
- Free, no obligation quotes
- Local licensed contractors
- Faster than manual estimating
Frequently Asked Questions
How big a shed can I build without a permit?
Under the model residential code (IRC), a one-story detached shed up to 200 square feet doesn't need a building permit. But your state or city may use a different number: California uses 120, Virginia 256, New Jersey 200 with a 10-foot height limit, Houston 120, Chicago 150, the City of St. Louis 50, and Tucson requires a permit for every shed. Check with your local building department before you buy.
Is it 120 or 200 square feet?
Both are real, for different buildings. The IRC, which covers houses, exempts sheds up to 200 square feet. The IBC, which covers commercial and other non-residential property, exempts tool and storage sheds up to 120 square feet. Some states and cities, including California and Houston, also use 120 square feet for sheds at homes.
Do I still need zoning approval for a small shed?
Often, yes. The permit exemption covers only the building permit. Setbacks from property lines, lot coverage, front-yard rules and the number of accessory buildings come from local zoning, and many towns require a zoning permit or registration even for sheds that are exempt from a building permit. In Pennsylvania, for example, sheds the state building code excludes can still need a local zoning permit.
Do I need a permit to put electricity in a shed?
Almost always. Even when the shed itself is exempt, running power, plumbing or gas to it needs its own trade permit. New Jersey's rule says this directly, and Phoenix's code commentary says a permit is required to install utilities in an exempt shed. Some exemptions, like New Jersey's and Chicago's, also disappear if the shed has a water, gas or sewer connection or plumbing.
Does a shed on a concrete slab need a permit?
It can. Some jurisdictions only exempt sheds that sit directly on grade, and a poured slab or permanent foundation can trigger a permit or specific foundation rules. Ask your building department before pouring. If you do pour, size the pad with the concrete calculator; for a gravel base, use the gravel calculator.
Do pre-built sheds need a permit?
The same size limits apply whether a shed is built on site or delivered in one piece. Before delivery, confirm the size limit, setbacks and delivery access, and whether your town requires a location permit, registration or anchoring for sheds.
Where do these numbers come from?
The model-code numbers were read directly from the 2021 and 2024 IRC and the 2024 IBC on ICC Digital Codes. Each state and city limit on this page was read in that state's adopted code or regulation, or on the city's own code or permit page; North Carolina's rule is quoted as county building departments publish it. States we couldn't confirm from primary text are not given a number here, because a wrong number is worse than none.
Related Code Guides
Deck Guardrail Height and Permit Rules by State
Why deck guard height is 36 inches almost everywhere except California (42), and why some states, like New Jersey, require a permit for any deck at all.
Residential Building Code Edition by State: IRC, NEC, and Energy Code
Which IRC, NEC and energy code edition each state has adopted for homes, with effective dates, pending updates, and states with no statewide code.
Frost Depth by State: How Deep Footings Must Go
How deep footings must go: the IRC 12-inch rule, frost depths from 11 state codes, county tables for MN, IN, OR and KY, and what is exempt.