Longmont, CO Accessory Structures: Shed & Carport Rules (2026)
Shed permit rules in Longmont, CO, 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 shed size
- 200 sq ft (18.58 sq m) or less, one story
- Covered uses
- Tool sheds, storage sheds, playhouses, similar structures
- Governing code
- 2024 IRC as amended by Ord. No. O-2026-24
- Effective date
- June 9, 2026
- Setback, over 120 sq ft
- Minimum 5 feet from property line
- Setback, under 120 sq ft
- Minimum 3 feet, capped at 50% of setback area
- Default penalty
- Up to $500 fine, 90 days jail, per day
Summary
Longmont exempts small detached accessory structures, tool sheds, storage sheds, playhouses and similar buildings, from a building permit only when they are one story and the floor area is 200 square feet or less. Anything bigger triggers a full building permit under the 2024 International Residential Code as amended by the city, plus the zoning setback rules that apply to accessory structures on the lot.
Section R105.2 of the International Residential Code is amended by the revision and deletion of the following subsections listed under Building: Subsection 1 is replaced with the following: 1. One-story detached accessory structures used as tool and storage sheds, playhouses and similar uses, provided that the floor area is 200 square feet (18.58 m 2 ) or less.
Full Breakdown
2 of the 2024 International Residential Code, the code's list of work exempt from a building permit, as adopted through Ordinance No. 06. 58 square meters) or less, and it deleted subsections 2 and 10 of the model list outright rather than adopting them locally. A shed under the 200-square-foot line needs no building permit, no plan review and no inspection for the structure itself. 080. 070, and the building official can grant extensions of up to 180 days for written, justified cause. Falling under the permit-exemption threshold does not exempt a shed from Longmont's zoning code.
040 of the Land Development Code requires any accessory structure over 120 square feet to sit at least five feet from the property line, while a smaller structure needs only three feet of separation but cannot cover more than half of the combined required rear and side setback area, and must be sited to accommodate lot drainage. 140 separately defines a detached structure as an accessory building set at least five feet from the principal structure. Residential accessory structures, permit-exempt or not, also cannot exceed 50 percent of the principal structure's floor area (75 percent combined) and cannot stand taller than the house itself.
Violations & Fines
Building or altering a shed above 200 square feet without a permit is an unlawful act under Section R113.1, as replaced by Section 16.06.130, and it counts as a separate offense for every day the violation continues. Longmont prosecutes unpermitted construction under Chapter 1.12, which sets a default fine of up to $500.00 and up to 90 days in jail under Section 1.12.010 unless another Code section states a different penalty, and the city attorney can also seek a court injunction treating the unpermitted structure as a public nuisance.
Frequently Asked Questions
Do I need a permit for a backyard shed in Longmont?
What happens if my shed is bigger than 200 square feet?
Does a permit-exempt shed still have to meet setback rules?
What can happen if I build an oversized shed without a permit?
Can I appeal a building official's decision about my shed permit?
Sources & Official References
Other rules in Longmont
How Longmont compares: Shed Permit Requirements by City·Compare Longmont to another location·View the Colorado accessory structures overview
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