Guide
Do I need a permit for a shed?
Often not for a small shed, but only your town can tell you. The model codes that US building codes are usually built on exempt one-story detached accessory buildings up to 200 square feet (International Residential Code, Section R105.2) or tool and storage sheds up to 120 square feet (International Building Code, Section 105.2) from a building permit, and many towns change those numbers.
Even when no building permit is needed, the shed still has to meet the town's other rules: zoning setbacks from the property line, height limits, how much of the lot can be built on, easements and any HOA approval. Both codes say an exemption is not permission to break the code or any other local law.
- Residential code (IRC R105.2)
- no permit for one-story detached accessory buildings up to 200 sq ft
- Building code (IBC 105.2)
- no permit for tool and storage sheds up to 120 sq ft
- Still applies
- zoning setbacks, height limits, HOA rules, electrical permits
- Who decides
- your city or county building department and zoning office
The 200 and 120 square foot rules
Many states and towns adopt the International Code Council's model codes and then amend them. The International Residential Code covers houses and the buildings that go with them; its Section R105.2 lists work that needs no permit, starting with one-story detached accessory structures with a floor area of no more than 200 square feet. The International Building Code, for other buildings, exempts one-story tool and storage sheds, playhouses and similar buildings up to 120 square feet.
Both open the list with the same sentence: an exemption does not authorize work that breaks the code or any other law of the town. In practice a shed you may build without a permit must still meet the building code, and zoning.
Your town's number may be different
Towns adopt these codes with changes. Some keep 200 square feet as written (Federal Way, Washington, lists it word for word); others lower it to 120, add a height limit, or exempt only sheds that sit a set distance from the property line. A county and the town inside it can differ, and the rules can change when a new edition is adopted. The only reliable answer is your own building department's, ideally in writing.
Which shed sizes are under 120 and 200 square feet
Floor area is usually measured to the outside of the walls; ask whether a roof overhang or a porch counts. Here is where each of our plan sizes falls against the two model numbers:
- At or under 120 sq ft: 4x8, 6x8, 8x8, 8x10, 8x12, 10x10, 10x12.
- 121 to 200 sq ft: 8x16, 10x14, 12x12, 10x16, 12x14, 12x16, 10x20.
- Over 200 sq ft: 12x18, 14x16, 12x20, 16x16, 16x20.
| Shed | Floor area | Inside which exemption | Height |
|---|---|---|---|
| 8x8 gable | 64 sq ft | inside both | 11' 5-15/16" |
| 8x10 gable | 80 sq ft | inside both | 11' 5-15/16" |
| 8x12 gable | 96 sq ft | inside both | 11' 5-15/16" |
| 10x10 gable | 100 sq ft | inside both | 11' 11-15/16" |
| 10x12 gable | 120 sq ft | inside both | 11' 11-15/16" |
| 10x14 gable | 140 sq ft | residential code only | 11' 11-15/16" |
| 10x16 gable | 160 sq ft | residential code only | 11' 11-15/16" |
| 12x12 gable | 144 sq ft | residential code only | 12' 5-15/16" |
| 8x16 gable | 128 sq ft | residential code only | 11' 5-15/16" |
| 12x14 gable | 168 sq ft | residential code only | 12' 5-15/16" |
| 12x16 gable | 192 sq ft | residential code only | 12' 5-15/16" |
| 12x18 gable | 216 sq ft | neither | 12' 5-15/16" |
| 10x20 gable | 200 sq ft | residential code only | 11' 11-15/16" |
| 12x20 gable | 240 sq ft | neither | 12' 5-15/16" |
| 14x16 gable | 224 sq ft | neither | 12' 11-15/16" |
| 16x16 gable | 256 sq ft | neither | 13' 5-15/16" |
| 16x20 gable | 320 sq ft | neither | 13' 5-15/16" |
| 4x8 lean-to | 32 sq ft | inside both | 10' 8-1/4" |
| 6x8 lean-to | 48 sq ft | inside both | 11' 2-1/4" |
| 8x8 lean-to | 64 sq ft | inside both | 11' 8-1/4" |
| 8x10 lean-to | 80 sq ft | inside both | 11' 8-1/4" |
| 8x12 lean-to | 96 sq ft | inside both | 11' 8-1/4" |
| 10x10 lean-to | 100 sq ft | inside both | 11' 3-7/8" |
| 10x12 lean-to | 120 sq ft | inside both | 11' 3-7/8" |
| 10x14 lean-to | 140 sq ft | residential code only | 11' 3-7/8" |
| 12x12 lean-to | 144 sq ft | residential code only | 11' 9-5/8" |
A 10x12 shed is exactly 120 square feet, the most the building code's exemption allows, while a 10x14 (140) is over it. Heights run from 10' 8-1/4" (4x8 lean-to) to 13' 5-15/16" (16x16 gable); if your town caps the height of sheds, a lower roof pitch or a lean-to brings it down (see shed roof pitch).
Zoning, setbacks and HOAs: the rules that still apply
- Setbacks: how far a shed must stand from the side and rear property lines, other buildings and the street. Some towns do not allow sheds in a front yard at all.
- Height: often measured to the highest point or the midpoint of the roof; ask which.
- Lot coverage and number of buildings: a limit on how much of the lot can be covered, or how many accessory buildings you may have.
- Easements and utilities: no building over a utility easement or a septic field. Call 811 before you dig.
- Flood zones and historic districts: extra rules, sometimes a permit for any building.
- HOA covenants: approval of size, color and location, separate from the town.
A shed on skids is still a building to many zoning codes, even though it could be moved; check before you assume otherwise.
What to ask the building department and zoning office
- Does a one-story shed of this floor area need a building permit here? Which code edition and amendments do you use?
- How is floor area measured: outside of the walls, and does the overhang count?
- What is the height limit for an accessory building, and how is it measured?
- What are the setbacks from the side and rear lot lines, other buildings and the house?
- Do I need a zoning permit or a site plan even if no building permit is needed?
- Does the foundation need frost-protected footings for this size?
- Do I need an electrical permit to run power to it?
Write down who you spoke to and when, or ask for the answer by email.
If you do need a permit: what they usually ask for
For a shed, a permit office usually wants a site plan (the lot, the house and the shed with the distances to the property lines), drawings of the shed (floor plan, elevations, a cross section through the wall and roof) and the framing details: joist, rafter and header sizes and the foundation. Fees and inspections vary from town to town.
Our plans give you dimensioned drawings, every member size and a full materials list to take to the counter. For a 10x12 the drawings are: Floor framing plan; Front wall framing; Back wall framing; Left wall framing; Right wall framing; Rafter template (full size); Front elevation. They are a guide drawn to common light-frame practice, not drawings stamped for your site, so your building department may ask for changes.
Power, plumbing and lofts
The exemptions above are for the building. Running electricity, water or gas to a shed is a separate trade, and many towns want a permit for it whatever the shed's size. A loft you can stand in or a second floor can also take a shed out of the one-story exemption. Ask about each before you build them in.
Questions people ask
What size shed can I build without a permit?
It depends on your town. The International Residential Code exempts one-story detached accessory buildings up to 200 square feet, and the International Building Code exempts tool and storage sheds up to 120; many towns use one of these numbers or their own. Zoning rules apply either way.
Do I need a permit for a 10x12 shed?
A 10x12 shed is 120 square feet, inside both model exemptions, so many towns do not require a building permit for it. Some do, and zoning setbacks and height limits still apply, so ask your building department.
Do I need a permit for a shed on skids?
Usually the same as for any other shed: many towns treat a shed on skids as a building, even though it can be moved. Ask your building department and zoning office.
Do I need a permit for a 12x16 shed?
A 12x16 shed is 192 square feet, over the building code's 120 square feet but under the residential code's 200, so the answer depends on which number your town uses.
Can I put electricity in a shed without a permit?
Often not: in many towns electrical work needs its own permit, even when the shed itself needs none. Ask your building department.
Take a plan to the counter
See what our plans include on the 10x12 gable shed plans page, or price any size in the free materials calculator before you ask.
Sources
- Washington State IRC 2018, Section R105.2, as published by the City of Lynnwood: the 200 square foot exemption and the "not authorization" sentence
- International Code Council, 2021 IBC Section 105.2 (in a committee proposal): the 120 square foot exemption for tool and storage sheds
- City of Federal Way, residential permit exemptions (IRC R105.2): a town that adopts the 200 square foot number
- Call 811: free marking of buried utility lines before you dig
Our plans and these guides follow common light-frame building practice and are a guide, not drawings stamped for your site: check your local codes, permit rules and HOA before you build. Nothing here is legal advice; your building department has the final word.