Shawnee requires a building permit for "any accessory building over 120 square feet (10 feet by 12 feet)" and — the rule that surprises people — allows "only one accessory building per residential lot." If you already have a shed, a pavilion may not be permitted as a second building; ask before you design. Small structures up to 250 square feet sit 5 feet from side and rear lines and outside utility easements; larger ones meet the district's bulk setbacks. The bottom of the foundation must be 36 inches below grade only when the building exceeds 400 square feet, and a Johnson County contractor's license is required above that same size. Read from Shawnee's Detached Accessory Building Guidelines and FAQ on September 30, 2026.
What's different in Shawnee
One accessory building per lot. From the city FAQ: "Only one accessory building is allowed per residential lot" (Shawnee FAQ, building, accessed 2026-09-30). Whether an open-sided pavilion counts as a "building" alongside an existing shed is the first question we ask Codes Administration on any Shawnee lot that already has a structure.
Two size lines that matter. 250 square feet changes the setback (5-foot rule below, district setbacks above). 400 square feet changes the footing (36-inch depth required above) and the licensing (Class A, B or C Johnson County license required above). A 16×20 pavilion is 320 square feet — over the first line, under the second. A 20×24 at 480 square feet crosses both (Detached Accessory Building Guidelines, accessed 2026-09-30).
Rear yard only, 5 feet off the house. "Accessory buildings and structures shall be placed in the rear yard only," and buildings over 120 square feet must be at least 5 feet from the principal building.
A mixed code set. As of April 1, 2026 Shawnee builds to the 2024 International Building Code, the 2023 National Electrical Code and the 2018 International Residential Code (Building Permits & Inspections, accessed 2026-09-30). The guideline says accessory buildings "shall be constructed as required by the 2018 International Building Codes."
Does your pavilion need a permit?
| Pavilion | Building permit | Setback | Footing depth rule | License |
|---|---|---|---|---|
| 10×12 (120 sq ft) | No | 5 ft, outside easements | none stated | — |
| 12×16 (192 sq ft) | Yes | 5 ft / 5 ft, outside easements | none stated in guideline | occupational license |
| 16×20 (320 sq ft) | Yes | district bulk setbacks | none stated in guideline | occupational license |
| 20×24 (480 sq ft) | Yes | district bulk setbacks | 36 in | JoCo Class A/B/C |
Electrical work needs its own permit at any size, and the application asks you to state whether electrical, plumbing or HVAC is included.
Zoning: where it can go
- Rear yard only; at least 5 feet from the house (over 120 square feet).
- 250 square feet or less: at least 5 feet from side and rear property lines and outside any utility easement.
- Over 250 square feet: the zoning district's side and rear bulk setbacks (check your district; R-1 rear yards are commonly 20–30 feet).
- Size caps on lots of an acre or less: 250 square feet per 3,000 square feet of lot area; no more than 30 percent of the required rear yard; no larger than the finished area of the house; never more than 1,000 square feet.
- No accessory building on a vacant lot.
Example. A 16×20 pavilion on a 10,000-square-foot lot: size cap 833 square feet (fine), but at 320 square feet the pavilion must meet the district's rear and side setbacks rather than the 5-foot rule — and if a shed is already on the lot, the one-building rule comes first.
Codes, footings and drawings
The guideline's submittal list is the most specific in the metro: an application; a plot plan drawn to scale with distances to property lines and buildings; electronic plans showing "foundation details, and how the building is attached to the foundation" and "size, species, spacing, and grade of all framing members." Trusses need original Kansas engineer's seals, and post-frame buildings need a Kansas engineer's seal — a post-and-beam pavilion is neither, but the city's permits page separately says design-professional plans are required "for all buildings," so we confirm which statement governs a pavilion before quoting drawings. Fees are based on project valuation.
Who can pull the permit
A Shawnee occupational license is always required; above 400 square feet the contractor must also hold a Johnson County Class A, B or C license. Homeowner-as-contractor rules were not in the guideline.
What we handle
The one-building question first; sizing to the 250- and 400-square-foot lines; the plot plan with easements; framing schedule with species, size, spacing and grade; foundation-attachment detail; the electrical permit through a licensed electrician.
Not verified online — we confirm before submitting
Whether an open pavilion counts as a second "accessory building"; height cap; whether the design-professional requirement reaches accessory structures; ground snow and wind values; fee schedule; inspection list.
Frequently asked questions
I have a shed. Can I add a pavilion? Shawnee allows one accessory building per residential lot. Ask Codes Administration whether an open-sided pavilion is treated as a second building before you plan one; the answer decides the project.
Does a 16×20 need 36-inch footings? The guideline requires the 36-inch depth above 400 square feet, so not by rule at 320 square feet. We will still recommend the footing the structure needs and explain why.
Is a kit different? No. Size and the one-building rule apply to kits too.
Last updated: September 30, 2026. Compare: Lenexa · Overland Park · all jurisdictions. Get a quote or run the Instant Estimate.