Question: Do I need a permit to build a greenhouse?

Greenhouses:

North Carolina General Statute �143-138 regulates building permit requirements for farm buildings as well as Greenhouses. In essence, if the greenhouse meets all the specifications of a greenhouse indicated in the definition below, than a building permit will not be required. HOWEVER, all other trade permits will be required, such as an electrical permit, plumbing permit, and/or mechanical permit if these items are installed in or on the greenhouse.

§ 143-138(b4) North Carolina State Building Code

(1) A "greenhouse" is a structure that has a glass or plastic roof, has one or more glass or plastic walls, has an area over ninety-five percent (95%) of which is used to grow or cultivate plants, is built in accordance with the National Greenhouse Manufacturers Association Structural Design manual, and is not used for retail sales. Additional provisions addressing distinct life safety hazards shall be approved by the local building‑rules jurisdiction.

A copy of the above stated design manual can be found online here

In summary, if the greenhouse meets all aspects of the definition above, a building permit will not be required regardless of whose jurisdiction it is located in.