Permits
Do You Need a Permit for a Greenhouse?
4 min · Updated 2026-09-28
No permit list names a greenhouse: the small-building lines one would have to fit, 200 sq ft in the model code and Austin, 120 in LA, and who decides.
None of the permit-exemption lists this page read names a greenhouse. A backyard greenhouse would need no building permit only by fitting a line such as the ones for small accessory buildings below, and the lines differ: 200 square feet in the model code and in Austin, 120 in Los Angeles, each with its own conditions, such as height, plumbing or wiring, and where the building stands. Whether a greenhouse fits a line is the building department’s call in both cities, so ask before you buy a kit, whatever its size.
| Condition | Model code (IRC) | Austin | Los Angeles |
|---|---|---|---|
| Floor area up to | 200 sq ft | 200 sq ft | 120 sq ft |
| Height | One story | One story, 15 ft or less | One story |
| Plumbing, heating, wiring | No condition in this line; the code’s other rules still apply | No plumbing | No heating, plumbing or electrical installation |
| Where | Detached, on the same lot as the house | Detached, not in a flood hazard area | Detached, outside Fire District No. 1, where Chapter I of the LAMC allows |
| Other | Not a storm shelter | Creates no dwelling | Used as a tool or storage shed, playhouse or similar use |
The model code
The 2024 International Residential Code needs no permit for a one-story detached accessory structure, other than a storm shelter, with a floor area of 200 square feet or less (R105.2). It defines an accessory structure as one incidental to the dwelling and on the same lot (R202). It does not name greenhouses, so the city or county that adopted it decides whether yours counts, and an exempt building must still meet the code and local law.
Austin
Austin replaces the model code’s list with its own, for one- and two-family houses and townhouses of three stories or less. A one-story detached accessory structure needs no building permit if it has no more than 200 square feet of floor area, stands no more than 15 feet tall, creates no dwelling, contains no plumbing and is not in a flood hazard area. The list names no greenhouse, so Development Services decides whether one fits: 512-978-4000. The electrical list exempts wiring and equipment under 25 volts that can supply no more than 50 watts, and the mechanical list a portable heating or ventilation appliance; for household-voltage wiring to lights, fans or a heater, or a fixed heater, ask Development Services. Exempt work must still meet the building codes and city codes.
Los Angeles
Los Angeles’s building code does not apply to one-story detached accessory structures used as tool and storage sheds, playhouses and similar uses, up to 120 square feet, outside Fire District No. 1, with no heating, plumbing or electrical installation, and located as Chapter I of the Municipal Code permits (LAMC 91.101.5, item 1). A greenhouse is not named, so whether it is a similar use is for the Department of Building and Safety to say. The same section lists pergolas and lath houses outside any fire district, up to 400 square feet and not supported by or attached to a building (item 7); it does not name a greenhouse there either. Work the code covers needs a permit (LAMC 91.106.1.1), so for a greenhouse that fits neither item, ask the Department what it needs.
Where it stands and what it sits on
Whatever the building code says, zoning still applies, including how close a greenhouse may stand to the lot lines; the shed setback guide covers that, and the shed permit brief gives each city’s line for small buildings in full.
The model code needs no frost protection for a free-standing accessory structure of light-frame construction up to 600 square feet, or of other construction up to 400, with an eave no higher than 10 feet; the frost line guide explains what that covers and where to ask.