How is Derby's code different from Wichita's?
Derby sits about 10 miles southeast of downtown Wichita, straight-line from the city's coordinates. It runs its own code. Ordinance 2623, passed December 9, 2025 and published December 17, 2025, adopted the 2024 IRC. Wichita and unincorporated Sedgwick County still build to the 2018 IRC under Ord. 50-833.
| Item | Derby (Ord. 2623) | Wichita (Ord. 50-833 / Res. 080-2017) |
|---|---|---|
| Residential code | 2024 IRC | 2018 IRC |
| Building-permit exemption | One-story detached accessory ≤200 sq ft, with a city accessory structure permit | ≤200 sq ft, with an MABCD location permit |
| Anchoring | 25–400 sq ft: concrete foundation or listed earth anchors | 25–400 sq ft: anchored or concrete foundation |
| Hoop houses | Residential poly hoop houses excluded from building code | Same exclusion (Sec. 2.4.035, UBTC) |
| Accessory buildings ≥200 sq ft | Must match the house in at least two of roof style, siding, color or similar design features | No design-match rule in the building code |
| Frost depth | 24 in. | 24 in. |
| Frost-protection exemption | Freestanding ≤400 sq ft, eave ≤10 ft | Same |
| Ground snow / wind in local table | 15 psf; "76 w/90-3 sec. gust" | 15 psf; "76w/90-3 sec. gust" (MABCD table) |
The wind row needs care. Derby's "76 w/90-3 sec. gust" is the same older value as MABCD's table (Sec. 2.4.115, UBTC): 76 mph fastest-mile = 90 mph 3-second gust, one design wind written two ways (IBC Table 1609.3.1). Today's maps use a 115 mph ultimate speed (Meltplan); in allowable-stress terms, 115 × √0.6 = 89.1 mph, in line with the 90 mph gust. Derby is not calmer than Wichita; the tables match. On snow, the code minimum in both is 15 psf. We still size kits and frames to at least 20 psf as a margin.
What does Derby's hoop-house exclusion cover?
Item 15 of Derby's permit exemptions reads: "'Hoop Houses' shall be excluded from building code requirements." The ordinance defines a hoop house as "a poly-tunnel (also known as a poly-house, hoop greenhouse or hoop house, or high tunnel) made of polyethylene." It closes with: "Hoop houses, within this definition, are for residential use only."
In practice:
- A backyard poly tunnel for your own garden fits the definition.
- A polycarbonate or glass greenhouse does not. It follows the normal 200 sq ft rule.
- A tunnel used to grow for sale does not fit "residential use only."
- The exclusion is from the building code. Setbacks, easements and floodplain rules still apply. Derby's documents don't say whether a hoop house still needs a zoning or accessory permit, so ask the city.
Our high tunnel installation page covers tunnel sizes, end walls and anchoring.
What Derby's accessory permit asks for
Derby's accessory structure permit application (revised July 2025) is a short form with a $25 fee and a required inspection. It asks for a plot plan with property lines, easements and existing structures. The form's certification lists the rules that shape where a greenhouse can go:
- Same front and side setbacks as the house, and at least 5 ft from the rear lot line.
- No taller than 21 ft in residential districts (the zoning code caps accessory structures at 80% of the district height limit).
- At 200 sq ft or more, it must match the house in at least two of roof style and material, siding, color scheme or similar design features (Sec. 600.C.5, Derby zoning). A 12 × 20 glass house (240 sq ft) is caught; a 10 × 16 (160 sq ft) is not.
- Not over a utility easement unless the structure is movable. Anything on a permanent foundation stays out of easements.
- Lot coverage limits apply. The form has you total the house, garage, deck and accessory buildings.
- In a FEMA hazard area, a floodplain development permit may be needed.
One wrinkle: the July 2025 form still describes itself as covering structures "up to and including 119 square feet" and cites the 2018 IRC. The December 2025 ordinance sets the line at 200 sq ft. Call Derby's planning office to confirm which threshold they apply. The permit guide compares every jurisdiction.
What soil is under a Derby greenhouse?
We sampled a nine-point grid across Derby, spaced about a mile apart, in NRCS Soil Data Access (Sedgwick County survey, KS173). The town splits three ways.
| Soil (NRCS map unit) | Points | What it means for a foundation |
|---|---|---|
| Vanoss silt loam, 1–7% slopes | 4 of 9 | Well drained, hydrologic group B; moderate shrink-swell (linear extensibility 4.6%) |
| Irwin silty clay loam | 2 of 9 | Clay up to 45%, high shrink-swell (7.4%), group D; drains slowly |
| Waldeck, Elandco (creek bottoms) | 2 of 9 | Occasionally flooded; Waldeck's water table can sit about 92 cm (3 ft) down |
| Saltcreek and Naron fine sandy loams | 1 of 9 | Well drained, sandy |
A separate point on Derby's west edge maps as Lincoln soils, "frequently flooded."
On Vanoss uplands, a standard perimeter footing or post foundation works. On Irwin clay, the soil swells when wet and shrinks in drought, so piers to 24 inches or deeper and good drainage away from the slab matter. Derby's code points to the same concern. Its amended R403.1.8 sends foundations on expansive soils to the Wichita Foundation, Basement and Slab-on-Grade Standards (2011). In a creek bottom, check the flood map and the water table before you dig. We confirm soil on site before we design; a map unit is a starting point, not a soil test. See greenhouse foundations.
Hail and sun in Derby
On September 15, 2010, the supercell that dropped the 7.75-inch stone NWS called a likely Kansas record kept going southeast "near Haysville, Derby," per the National Weather Service. NWS also logged a tornado 7 miles west of Derby that evening. Glazing choice matters here; see the hail-resistant glazing guide.
At 37.55°N, December 21 solar noon is 90 − 37.55 − 23.44 = 29.01°, so a wall shades 1/tan(29.01°) = 1.80× its height on the ground behind it.
Who builds greenhouses in Derby?
Derby is inside our core service area: Sedgwick County and towns within about 30 miles of Wichita. Pricing depends on size, glazing and foundation. National cost guides put most backyard greenhouses at $10 to $35 per sq ft (Angi); we quote your actual build. Haysville and Rose Hill are covered on our service area page.
Frequently asked questions
Do I need a permit for a greenhouse in Derby, KS?
Not a building permit, if it is one-story, detached and 200 sq ft or less. You still need a city accessory structure permit, and anything from 25 to 400 sq ft must be anchored or on a concrete foundation.
Are hoop houses exempt in Derby?
Residential hoop houses made of polyethylene are excluded from Derby's building code, as they are under the Wichita–Sedgwick County code. Commercial tunnels and rigid-glazed greenhouses are not. Setbacks and easements still apply; ask the city whether a zoning permit is needed.
What is the frost depth in Derby?
24 inches. Freestanding accessory structures of 400 sq ft or less, with an eave height of 10 ft or less, are exempt from frost protection.
How far from the property line does a greenhouse have to be in Derby?
Derby's accessory permit form requires the same front and side setbacks as the house and at least 5 ft from the rear lot line.
Which building code does Derby use?
The 2024 International Residential Code, adopted by Ordinance 2623 in December 2025. Wichita still uses the 2018 IRC.
Get a quote
Send us your Derby address, the footprint you have in mind and whether it's a hoop house or a glazed greenhouse. We'll check your setbacks, soil and permit path, then price the build.