Do you need a permit for a shed?

The two numbers that decide it

The International Residential Code, which most US towns adopt in some form, lists work that does not need a building permit. Section R105.2 includes one-story detached accessory structures used as tool and storage sheds, playhouses and similar uses, as long as the floor area is no more than 200 sq ft.

Many towns change that number when they adopt the code. The most common local limit is 120 sq ft, the figure older code editions used and the commercial code (IBC 105.2) still uses. Some towns go lower, some exempt nothing at all. The only way to know is to ask your building department.

Common shed sizes against both lines

A 10x12 shed is exactly 120 sq ft, which is why it is the most common shed size in the country. A 12x16 sits under 200 sq ft but over 120.

What still applies without a permit

• Setbacks. Zoning sets how close a shed may sit to property lines, the house and other buildings. Three to ten feet is typical.
• Height. Many zoning codes cap the height of accessory buildings. Each plan here lists its height from the ground.
• Easements. Nothing permanent over utility easements or a septic field.
• Electric and plumbing. Running power to a shed usually needs an electrical permit even when the shed does not.
• HOA rules. An HOA can limit size, color, siding and placement regardless of what the town allows.

What to tell the building department

Call or email with five facts and you will usually get a clear answer the same day: the floor size, the height from the ground, the distance to each property line, what it sits on (skids on gravel, blocks, or a slab), and whether it will have power.