Olathe exempts one-story detached accessory structures of 200 square feet or less from a building permit and lists pergolas and gazebos by name among the accessory structures that need one above that. Footings go 36 inches below grade, the design wind speed is 115 mph, an ice-barrier underlayment is required on the roof, and the zoning code keeps a pavilion 5 feet from rear and side lines, 10 feet from the house, under 25 feet at the ridge and out of every drainage and utility easement. Olathe publishes nearly all of this on its own code site, which is why it is the easiest metro city to plan a pavilion in — with one open question about drawings. Read from the code on September 30, 2026.
What's different in Olathe
The numbers are in the code, not a handout. Olathe's amended Table R301.2(1) states the frost line depth as "36-INCHES," the wind speed as 115 mph, weathering as "SEVERE," termites "YES," and ice barrier underlayment "Yes" (Olathe Municipal Code 15.04.100, accessed 2026-09-30). Those four facts decide how deep your piers go, how the roof is fastened, and what goes under the shingles.
Pergolas and gazebos are permit types. The city's residential permits page lists "garages, carports, pergolas, gazebos, canopies" as accessory-structure permits (Olathe residential building and development, accessed 2026-09-30).
"Sealed construction documents." Olathe's permit application guide marks the RS permit type — Residential Accessory Structure, Deck and Shed — as requiring sealed construction documents, a scope of work, a site plan and a homeowner affidavit when the homeowner acts as contractor; engineering calculations and a sealed plot plan are not required (Olathe building permit application guide, accessed 2026-09-30). Whether a Kansas engineer's seal is literally required for a post-and-beam pavilion, or whether prescriptive drawings satisfy the reviewer, is the one thing we confirm with the Building Division on every Olathe job before we quote drawings.
Easements are off limits. "Accessory structures shall not encroach on a drainage or utility easement" (UDO 18.50.060, accessed 2026-09-30). Olathe subdivisions commonly carry a 10- to 15-foot rear utility easement; that strip is not buildable.
Does your pavilion need a permit?
The exemption is for "one-story detached accessory structures used as tool and storage sheds, playhouses and similar uses, provided the floor area is not greater than 200 square feet" (15.02.140). The parallel section in the residential chapter shows as repealed in June 2026, so we confirm the 200-square-foot figure is still the residential threshold when we submit.
| Pavilion | Building permit | Electrical permit | Zoning | HOA |
|---|---|---|---|---|
| 12×16 (192 sq ft), no power | No (confirm) | No | Yes | Almost always |
| 14×16 (224 sq ft) and larger | Yes (RS permit) | Yes if wired | Yes | Almost always |
Zoning: where it can go
From UDO 18.50.060: at least 5 feet from rear or side property lines (15 feet on the street side of a corner lot); at least 10 feet from the principal building; ridge height no more than 25 feet; total accessory coverage no more than 30 percent of the required rear yard; no encroachment on drainage or utility easements. The section also caps shed size by lot — 210 square feet on lots under 7,000 square feet, 3 percent of lot area from 7,000 to 13,000, and 400 square feet on larger lots. Whether an open pavilion is measured against the shed cap or treated separately is a question we ask the reviewer; on a 9,000-square-foot lot the shed cap would be 270 square feet, which a 16×20 pavilion exceeds.
Example. A 16×20 pavilion on a 9,000-square-foot lot: 5 feet off the rear and side lines, 10 feet off the back of the house, outside the rear easement, under 25 feet at the ridge — and a call to confirm which size cap applies.
Codes, footings and drawings
2018 International Residential Code, adopted by Ordinance 19-28 (15.04.010). Footings bottom at 36 inches. Roofs get an ice-barrier underlayment at the eaves. Olathe points residential applicants to the Johnson County deck guideline for construction details; the county's residential foundation guideline allows 12-inch footings for freestanding accessory structures of 600 square feet or less with eaves no higher than 10 feet — we do not assume Olathe applies that relief to a pavilion without asking.
Who can pull the permit
"Homeowners may serve as the contractor on their primary residence" with an executed homeowner affidavit. Otherwise a Johnson County Class A, B or C contractor's license covers the structure; a Class DE license covers the electrical work.
What we handle
Site plan, elevations and specs for your HOA and the city; the sealed-documents question answered before we quote; pier depth to 36 inches; ice-barrier underlayment as standard; electrical permit coordinated with a licensed electrician.
Not verified online — we confirm before submitting
Whether 200 square feet remains the residential threshold after the June 2026 code cleanup; whether "sealed construction documents" is literal for a pavilion; which size cap applies to an open structure; the ground snow load figure (Figure R301.2(6) — neighboring jurisdictions use 20 psf); fees and inspection list.
Frequently asked questions
Is 36 inches really necessary for a small pavilion? It is what the city's code table says. Some Johnson County jurisdictions relieve small freestanding structures to 12 inches; we ask Olathe rather than assume.
Can it go over the utility easement at the back of my lot? No. That is the one rule Olathe states with no exceptions.
How tall? Twenty-five feet measured at the ridge — more than any pavilion needs.
Last updated: September 30, 2026. Compare: Overland Park · Lenexa · all jurisdictions. Get a quote or run the Instant Estimate.