190 - Building permit exemptions. One-story detached accessory buildings in conjunction with a single family dwelling used as tool and storage sheds, playhouses and similar non-occupiable space, provided the floor area does not exceed two hundred square feet; and no mechanical or plumbing is to be installed.
Typically, planning consent is not necessary for a shed or outbuilding, if its proposed floor area is below 15 square metres, it does not include sleeping accommodations, and the whole structure does not exceed a height of 2.5 metres (if it is located within 2 metres of the property boundary).
Garden sheds that are larger than 200 square feet require a permit. Any size shed built in a mobile home park or multi-family zone is required to have a permit.
The quick and simple answer is: you usually don't need a permit if the shed is 120 square feet or less. In California, most jurisdictions have adopted the 120 square foot rule. If your shed area is larger than 120 square feet, it needs a building permit. If it's less than that, it doesn't.
Garden sheds, tool sheds, and play structures - Structures less than 200 square feet do not require a permit. See our Garden sheds, gazebos, and play structures handout.
You don't need a permit to build a shed if it meets all of these criteria: The total area (or “footprint”) of the shed's roof is 120 square feet or less. The shed is a single-story building. The shed sits on a simple concrete slab, pier blocks, or soil.
A building permit is permission to begin construction – a legal document that provides a permanent construction record to certify a building project met the current building code requirements and, when necessary, conformed to approved plans and specifications.