The decisions at a glance
| Decision | Wichita fact that drives it | What it usually means for your build |
|---|---|---|
| Footprint | City: detached accessory ≤200 sf exempt from a building permit, location permit still required. Unincorporated Sedgwick: ≤400 sf exempt, location permit also required (Ord. 50-833, Res. 080-2017) | Decide early whether you're designing to a threshold or building bigger and permitting |
| Anchoring | Anything over 25 sf up to 400 sf must be tied down or set on a permanent concrete foundation | No "just set it on the lawn" option, even for small kits |
| Foundation | 24" frost depth; accessory ≤400 sf with eave ≤10 ft exempt from frost protection | Clay east/south: piers or 24" footings. Sandy river valley: check the water table first |
| Glazing | 333 hail reports within 10 mi since 2004 (stormersite); 7.75" stone in west Wichita, 2010 (NWS Wichita) | Multiwall polycarbonate is the default; glass only with a plan for hail |
| Structure | MABCD table: 15 psf ground snow, "76w/90-3 sec. gust" wind (UBTC); about 115 mph ultimate on current maps | Engineered connections from glazing to frame to foundation; we design to at least 20 psf snow |
| Attached vs freestanding | The accessory exemptions above are written for detached structures | Attached usually means a building permit; freestanding gives you more options |
Decision 1: How big, and which side of the permit line?
Inside the City of Wichita, a one-story detached accessory structure up to 200 sq ft is exempt from a building permit. But the same section says the exemption applies only if "a location permit is obtained from the MABCD prior to installation" (Ord. 50-833). Exempt from a building permit is not the same as no paperwork.
In unincorporated Sedgwick County, the exemption is 400 sq ft (Res. 080-2017), and a location permit is still required there, just without the follow-up inspection. Suburban cities set their own rules. Derby, for example, adopted the 2024 IRC with its own exemption. The permit guide walks through each jurisdiction.
- 12 × 16 = 192 sq ft or 14 × 14 = 196 sq ft fits under the city's 200 sq ft line.
- 16 × 24 = 384 sq ft fits under the county's 400 sq ft line but needs a building permit inside Wichita.
- Anything over 400 sq ft needs a building permit in both.
Setbacks are a separate question from the size exemption. In Wichita and the unincorporated county, the Unified Zoning Code generally puts an accessory building at least 5 ft from the rear lot line, 3 ft from a side line in the back half of the lot, 3 ft from the house, off easements and not in front of the house; confirm for your lot. Designing to a threshold is fine. So is building the size you need and permitting it. The mistake is picking dimensions first and finding out about the line later.
Decision 2: What foundation does your soil call for?
Wichita's frost depth is 24 inches (Ord. 50-833). Freestanding light-framed accessory structures of 400 sq ft or less with an eave height of 10 ft or less are exempt from frost protection. Soil decides more than the code does here.
Sedgwick County soils fall into three broad groups in the NRCS soil survey (NRCS Soil Data Access):
| Soil group (NRCS series) | Where | Behavior | Foundation we'd plan around |
|---|---|---|---|
| Blanket, Nalim, Shellabarger | Much of the county uplands | Well drained; Blanket and Nalim hydrologic group C, Shellabarger mostly B; Blanket has a clay subsoil that can move | Treated sill on a concrete grade beam or piers; standard drainage |
| Irwin, Tabler, Rosehill | East and south of the county | Clay, shrink-swell, hydrologic group D | Piers or footings taken to 24"; positive drainage away from the slab; no slab poured on wet clay |
| Canadian–Waldeck | Arkansas River valley | Sandy alluvium; Canadian drains well, but Waldeck can carry a seasonal water table about 2–3 ft down | Check the water table before any below-grade work; shallow footings; avoid sunken floors |
Clay that swells and shrinks moves a rigid frame, and glazing doesn't forgive that. On clay sites we take footings or piers to frost depth even when the exemption would allow less.
On sandy river-valley soil, the question flips. Drainage is easy, but a shallow water table rules out a sunken or earth-sheltered floor in many spots. In the northwest county, the Equus Beds aquifer adds its own considerations for wells and irrigation — see our Equus Beds water guide.
Excavation is scoped per site, and concrete scope depends on the lot. Our greenhouse foundations page covers pier, grade-beam and slab options in more depth.
Decision 3: Which glazing can take Wichita hail?
Hail is a design load here: 333 hail reports within 10 miles of Wichita since 2004 (stormersite), and a 7.75-inch stone in west Wichita on September 15, 2010 (NWS Wichita). That sets up the choice:
- Multiwall polycarbonate (twin-wall 8 mm up to 16 mm triple- or five-wall) flexes instead of shattering, insulates better than single glass, and is the default for most Wichita builds.
- Tempered glass transmits the most light and lasts longest if intact, but can break under large hail. Choose it with a hail plan.
- Poly film is the low-cost option for hoop houses and high tunnels, replaced every few years.
Glazing also sets your heating bill. Conduction loss is roughly area × U-value × heating degree days × 24. For 500 sq ft of glazing and Wichita's 4,592 annual heating degree days (NOAA NCEI), single glass at U 1.1 (University of Arkansas) loses about 500 × 1.1 × 4,592 × 24 ≈ 60.6 million Btu a year. 16 mm triple-wall polycarbonate at U 0.40 (Gothic Arch) loses about 22.0 million Btu — roughly a third. Our heating guide turns this into fuel cost month by month.
The full material comparison is on our polycarbonate vs glass page. The storm record, impact ratings and warranty fine print are in the hail-resistant glazing guide. We'll tell you which panel lines fit your budget and hail exposure when we quote.
Decision 4: How is it anchored for Kansas wind?
MABCD's design table for Sedgwick County lists a 15 psf ground snow load and a wind speed of "76w/90-3 sec. gust" (Sec. 2.4.115, UBTC). That is one older value written two ways: 76 mph fastest-mile = 90 mph 3-second gust. Current maps give 115 mph ultimate for Risk Category II (meltplan), about 89 mph in allowable-stress terms, in line with MABCD's 90. We design to those wind figures and to at least 20 psf snow, above the 15 psf minimum. Exposure is set for your site.
A greenhouse is light with a large surface area, so uplift usually governs, not weight. The code recognizes this: detached accessory structures over 25 sq ft up to 400 sq ft "shall be tied down to the earth" using the City of Wichita's anchoring standards, or attached to a permanent concrete foundation per R403.1.6 (Ord. 50-833).
What we design for:
- A continuous load path: glazing to purlins, purlins to frame, frame to sill, sill to foundation.
- Panel fastening and edge capture matched to the panel maker's wind guidance.
- Doors and vents that latch closed, because an open door turns a greenhouse into a sail.
Our wind-rated greenhouse design guide shows how those loads translate into anchors and connections.
Attached or freestanding?
An attached (lean-to) greenhouse shares a wall with your house: easier to heat, reach and plumb. But the accessory exemptions are written for detached structures. An attached greenhouse is generally treated as part of the house, which usually means a building permit at any size. Confirm with MABCD for your address.
A freestanding greenhouse can sit where the sun is best. In Wichita, the December noon sun is about 28.9° above the horizon (90 − 37.69 − 23.44 = 28.87°). Any building, fence or tree south of the greenhouse casts a shadow about 1.81 times its height at that hour (1 ÷ tan 28.87°). A 6 ft fence shades roughly 11 ft of ground at midday in late December. Freestanding lets you site clear of that.
| Attached (lean-to) | Freestanding | |
|---|---|---|
| Permit | Usually a building permit | May fall under the 200/400 sf exemption, with a location permit |
| Heat | Shares house wall; lower heat loss | All sides exposed; more glazing area to heat |
| Sun | Limited to the house's south or west face | Sited for full winter sun |
| Hail | House wall protects one side | All surfaces exposed |
What our build process looks like
- Consultation. What you want to grow, how you'll heat it, roughly where it goes.
- Site visit. Sun, slope, soil, drainage, setbacks and utility access.
- Design. Footprint, foundation, frame, glazing and anchoring, drawn to your site and code.
- Permits. The location permit or building permit, as your jurisdiction requires.
- Build. Foundation, frame, glazing, doors and vents, then heat, ventilation, water and power.
Timing depends on season, permits and materials; your quote gives a schedule. Warranty terms are written into your quote; ask for workmanship and material coverage in writing.
What drives the cost?
We don't publish package prices until we've seen your site. For context, national cost guides put custom wood greenhouses at about $6,000–$15,000 (Angi) and attached greenhouses at $13,000–$35,000 (HomeAdvisor, Apr 2024). The main cost drivers are:
- Footprint and height. Glazing area grows faster than floor area as you go taller.
- Foundation. Piers on well-drained upland soil cost less than footings on shrink-swell clay.
- Glazing. 16 mm triple-wall costs roughly twice what 8 mm twin-wall does per sq ft in published panel prices.
- Systems. Heat, ventilation, water and electrical are often a large share of the total.
Frequently asked questions
Do I need a permit for a custom greenhouse in Wichita?
Inside the city, a detached greenhouse up to 200 sq ft is exempt from a building permit but still needs a location permit from MABCD. In unincorporated Sedgwick County the exemption is 400 sq ft, also with a location permit. Larger greenhouses and most attached greenhouses need a building permit. The permit guide has the details.
Does a small greenhouse need a foundation?
Any detached accessory structure over 25 sq ft up to 400 sq ft must be anchored to the ground or set on a permanent concrete foundation. Frost protection isn't required for freestanding accessory structures of 400 sq ft or less with a 10 ft or lower eave, but on clay soils we still take piers or footings to 24 inches.
Is polycarbonate or glass better for a Wichita greenhouse?
For most Wichita builds, multiwall polycarbonate. It handles hail better and insulates better than single glass. Glass transmits slightly more light and lasts longer if unbroken. See the polycarbonate vs glass comparison.
Can you build a sunken or earth-sheltered greenhouse?
Often, yes, but not on every lot. In the Arkansas River valley, Canadian–Waldeck soils can carry a seasonal water table about 2–3 ft down, which rules out a deep floor. We check soil and water before recommending it. More on our underground and earth-sheltered greenhouse page.
Get a quote
Tell us your lot, what you want to grow and roughly what size you have in mind. We'll come back with a design direction, the permit path for your address, and a quote.