St. Louis, MO Accessory Structures: Shed & Carport Rules (2026)
Shed permit rules in St. Louis, MO, also referred to as storage shed, backyard shed, or accessory building regulations, set size limits, setbacks, and when a building permit is required.
Key Facts
- Permit-exempt size
- 120 sq ft or less
- Permit-exempt height
- Under 12 feet
- Foundation required
- 4-inch concrete slab, anchored
- Setbacks
- Must still meet Zoning Code yards
- Hazardous-use sheds
- Permit required over 50 sq ft
Summary
St. Louis exempts small detached sheds from a building permit only if they are 120 square feet or less, under 12 feet tall, anchored to a 4-inch concrete slab, and set back per the Zoning Code.
Small detached accessory buildings, such as utility/storage/tool sheds, cabanas, play houses, etc., 120 square feet in area or less and less than twelve feet in height, provided the utility shed is placed on and anchored to a minimum four-inch-thick concrete slab and maintains the setbacks required by the Zoning Ordinance. This does not include accessory buildings having unique uses such as barbeque or smoke houses... A permit is required for all buildings housing these types of uses exceeding 50 square feet in area;
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 11).
Full Breakdown
Under the amended Building Code (§ 25.01.020, Section 105.2, item 26), a detached utility/storage/tool shed, cabana, or play house on a 1- to 2-family lot (or a building with up to four units) skips the permit process only if it is 120 square feet or smaller, stands less than 12 feet tall, sits on and is anchored to a concrete slab at least 4 inches thick, and still meets the front, side, and rear yard setbacks set by the Zoning Code. Sheds used for fuel storage, hazardous materials, or fuel-fired equipment don't qualify for the exemption and need a permit once they exceed 50 square feet. Anything larger or taller than the threshold requires a building permit from the Division of Building and Inspection before it goes up, and the shed still has to sit inside the zoning yard lines even when no permit is required.
Violations & Fines
Building without a required permit is enforceable by the Building Commissioner as a code violation, including stop-work orders and citation fines under Chapter 25; a shed placed inside a required yard setback is a zoning violation the Zoning Administrator can order corrected or removed regardless of size.
Frequently Asked Questions
Do I need a permit for a small backyard shed in St. Louis?
Can a permit-exempt shed sit anywhere in my yard?
Is a shed for storing fuel or a smoker exempt from permits?
Sources & Official References
Other rules in St. Louis
How St. Louis compares: Shed Permit Requirements by City·Compare St. Louis to another location·View the Missouri accessory structures overview
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