Quick answer: how big can a shed be without a permit?
There is no single nationwide shed size limit. A common baseline comes from the International Residential Code, which exempts certain one-story detached accessory structures of 200 square feet or less from the building permit requirement.
But that 200-square-foot number is not a universal rule for every U.S. property. States and local jurisdictions can amend the code or establish different requirements.
Current local examples show the difference. Seattle uses a 120-square-foot threshold for qualifying permit-free sheds, while Prince William County, Virginia identifies 256 square feet as a threshold for a one-story detached storage structure requiring a building permit in addition to zoning approval.
And even when a shed does not need a building permit, it may still have to comply with setbacks, zoning, easements, lot coverage, height and utility rules.
The question "How big can a shed be without a permit?" looks like it should have a simple answer.
Search Google and you will often see "200 square feet" repeated as if it were a nationwide law.
That is an oversimplification.
The 200-square-foot figure is a common International Residential Code baseline, but the actual rule controlling your property depends on the code adopted by your state and local authority, along with zoning and property-specific restrictions.
A 120-square-foot shed may be exempt in one city while a 200-square-foot shed is exempt somewhere else. Another jurisdiction may use a 256-square-foot threshold. Some places may require a building permit regardless of the shed's size under particular conditions.
This guide explains how to think about the rule correctly instead of relying on a generic "200 sq ft" answer.
What this guide covers
1. What Is the 200 Square Foot Shed Rule?
The frequently quoted 200-square-foot shed rule comes from the permit-exemption language used by the International Residential Code.
Section R105.2 of the 2024 IRC contains permit exemptions for certain work. The model-code framework includes an exemption for a one-story detached accessory structure with a floor area not exceeding 200 square feet.
This is the source of the number that appears in many shed-permit searches.
A common IRC exemption threshold for qualifying one-story detached accessory structures.
This is a model-code baseline, not a universal rule for every city and county in the United States.
The important word is "qualifying."
The exemption does not mean every structure under 200 square feet is automatically free from permits or other regulations.
2. Why the 200 Sq Ft Rule Is Not Universal
Building codes are adopted and administered by governments at different levels, and jurisdictions can modify the model-code provisions they use.
Local governments can also impose zoning requirements that are separate from the building permit exemption.
Adopted building code
A state may adopt a residential code with its own amendments and exemptions.
Local requirements
The local authority may impose different permit or zoning rules within its legal authority.
Site restrictions
Easements, flood zones, setbacks, overlays and HOA restrictions can affect the project.
So the correct answer is not "200 square feet."
The correct answer is: find the permit threshold and conditions that apply to your property.
3. Real Examples: 120, 200 and 256 Square Feet
Local government websites show just how different shed rules can be.
| Location | Example threshold | Important conditions |
|---|---|---|
| International Residential Code | 200 sq ft | One-story detached accessory structure; local adoption controls. |
| Seattle, WA | 120 sq ft | Single-story, detached, simple foundation, storage/growing use and other conditions. |
| Portland, OR | 200 sq ft | Non-habitable accessory structures; zoning permit may still be required. |
| Prince William County, VA | 256 sq ft | One-story detached storage structures over this size require building permit plus zoning approval. |
Seattle's official guidance says a shed does not need a permit when the roof footprint is 120 square feet or less and other conditions are met, including being single-story, detached and used for storage or similar generally unoccupied purposes.
Portland, Oregon, provides another example: non-habitable accessory structures of 200 square feet or smaller do not need a building permit, but a zoning permit may still be necessary.
Prince William County, Virginia, uses a different threshold and requires building permitting for one-story detached storage structures over 256 square feet, in addition to zoning approval.
These examples make the key point clear: your local rule matters more than the number you find on a generic shed website.
4. State Rules vs. Local Shed Rules
One of the most confusing parts of shed permitting is figuring out which government actually controls the requirement.
Some states establish residential building-code requirements at the state level. Others leave significant authority to cities and counties.
Even where a state code establishes an exemption, local zoning can still regulate the shed's location and use.
Building permit exemption ≠ permission to build anywhere
A shed may be exempt from a building permit while still needing to comply with zoning setbacks, lot coverage, easements, height restrictions and other land-use requirements.
That distinction is critical when researching a shed without permit.
5. How Is Shed Size Calculated?
Do not assume that every jurisdiction calculates shed area in exactly the same way.
Depending on the local rule, the measurement may be based on floor area, footprint or roof area.
For example, Seattle explicitly refers to the shed's roof footprint when describing its 120-square-foot permit exemption.
A 10 × 20 shed = 200 square feet
That does not automatically mean the shed is permit-exempt. You still need to determine whether your jurisdiction uses a 200-square-foot threshold and whether the shed satisfies all other exemption conditions.
Before ordering a shed, verify exactly how your local authority measures the applicable size limit.
6. Shed Height Can Matter Too
Size is not always the only condition.
Some jurisdictions impose height limits on accessory structures even when the shed is below the applicable floor-area threshold.
Portland, for example, states that a building permit is required for an accessory structure that is over 15 feet in height under the conditions described in its residential guidance.
Small but tall
A shed can fall below a size threshold and still encounter height-related restrictions.
Large but low
A low shed can still require a permit simply because its footprint exceeds the local exemption threshold.
7. Can a Shed Without a Permit Still Have Setbacks?
Yes.
This is one of the most important points homeowners miss.
A building-permit exemption does not automatically eliminate zoning requirements.
Your local zoning code may control how close the shed can be to:
Side and rear setbacks may apply.
Minimum separation from the primary structure may apply.
Front-yard and right-of-way restrictions can apply.
Utility, drainage and access easements can restrict placement.
Prince William County, for example, requires certain detached accessory structures to satisfy specific setbacks from property lines depending on the zoning district.
So "no building permit" should never be interpreted as "I can put the shed wherever I want."
Check the location before buying the shed
A shed that fits the size exemption can still be illegal if it violates the local setback or zoning rules.
8. Does Electricity or Plumbing Change the Permit Requirement?
It can.
A permit exemption for the shed structure does not necessarily exempt electrical, plumbing or mechanical work.
Electrical permit may apply
Running a new circuit or wiring can require separate electrical approval.
Plumbing work is different
Water, drainage or plumbing installations can create additional permit requirements.
Mechanical work
Heating or cooling equipment can trigger separate requirements.
If you want a shed with power, water, a bathroom or climate control, do not rely on the basic storage-shed exemption.
9. Can You Use a Permit-Exempt Shed as Living Space?
Generally, no—not simply because the structure is below the permit exemption size.
Shed exemptions are commonly written for detached accessory structures used for storage, tools, plants or similar non-habitable purposes.
Turning the structure into a bedroom, office, guest suite or dwelling can change its classification and trigger additional building and zoning requirements.
A 120 sq ft storage shed is not automatically a 120 sq ft dwelling.
Habitable spaces can involve requirements for egress, structural safety, insulation, ventilation, electrical systems, plumbing, energy efficiency, zoning and more.
10. Shed Permit Checklist Before You Build
Before purchasing or installing your shed, verify all of these items:
-
1. Determine the exact shed size.
Calculate the footprint using the method required by your local authority. -
2. Check your local permit threshold.
Do not assume the nationwide answer is 200 square feet. -
3. Check height restrictions.
Some jurisdictions regulate accessory-structure height separately. -
4. Confirm the shed is actually an accessory structure.
Use and classification can affect the exemption. -
5. Check setbacks.
Measure the proposed shed location from the relevant property lines. -
6. Check easements.
Utility, drainage and access easements can restrict placement. -
7. Check lot coverage.
The shed may count toward local coverage limits. -
8. Check utilities.
Electrical, plumbing and mechanical work can require separate permits. -
9. Check special property conditions.
Floodplains, environmental areas and historic districts may have additional rules. -
10. Check HOA restrictions.
Private HOA approval is separate from government permitting. -
11. Get written confirmation when the rule is unclear.
A local building or planning department can confirm the requirement for your property.
Shed Sizes: What They Mean
Here are common shed dimensions and their floor areas. These numbers are useful for planning, but they do not determine permit exemption by themselves.
| Shed dimensions | Area | Permit conclusion |
|---|---|---|
| 8 × 10 | 80 sq ft | Often below common thresholds, but local rules still apply. |
| 10 × 10 | 100 sq ft | May qualify in many jurisdictions; verify locally. |
| 10 × 12 | 120 sq ft | Meets Seattle's published size threshold, subject to all conditions. |
| 10 × 20 | 200 sq ft | Common IRC threshold, but not a universal exemption. |
| 12 × 20 | 240 sq ft | Exceeds the common 200 sq ft threshold. |
| 16 × 16 | 256 sq ft | A useful comparison because some local jurisdictions use 256 sq ft thresholds. |
Calculate your shed size before checking permit requirements
Use the Permitrust Shed Size Calculator to calculate your shed's square footage from its dimensions.
The calculation helps you compare your planned size with the applicable local threshold. It does not replace official zoning or permit verification.
Calculate Shed SizeMore shed permit resources
Don't assume "under 200 sq ft" means permit-free.
Your actual shed requirements can depend on your municipality, zoning district, shed size, height, location, utilities, use and property-specific restrictions.
Permitrust helps homeowners identify the permit and local requirements that may apply to a planned project.
Frequently Asked Questions About Shed Permits
How big can a shed be without a permit?
There is no nationwide size limit. A common model-code threshold is 200 square feet for a qualifying one-story detached accessory structure, but local rules can be smaller or larger.
Is a 200 square foot shed exempt from a building permit?
It can be where the local jurisdiction follows the applicable IRC exemption and the structure meets all conditions. The 200-square-foot rule is not universal.
Can I build a 10x20 shed without a permit?
A 10x20 shed is exactly 200 square feet, but that does not automatically make it permit-exempt. Your local jurisdiction and all applicable conditions determine the answer.
Does a shed need a permit if it is under 200 square feet?
Not necessarily. Some jurisdictions exempt qualifying sheds below 200 square feet, while others use lower thresholds or impose additional requirements based on height, location, utilities or use.
Does a shed without a building permit still need to meet setbacks?
Yes, potentially. Building-permit exemptions do not automatically eliminate zoning setbacks, easements or other land-use rules.
Can I put electricity in a shed without a permit?
Electrical work can require a separate permit even when the shed structure itself is exempt from a building permit.
Can I use a permit-exempt shed as a bedroom or living space?
Generally, no. A storage-shed exemption does not automatically authorize habitable or dwelling use. Additional building and zoning requirements can apply.
What happens if I build a shed without a required permit?
Depending on local law, you may face penalties, correction orders, additional permit costs or complications when selling or refinancing the property.
Official & Reference Sources
Shed permit exemptions are jurisdiction-specific. These sources demonstrate how the model code and local rules can differ.
- International Code Council — 2024 IRC, Section R105 Official model-code source for permit requirements and exemptions.
- City of Seattle — Sheds Official local example using a 120-square-foot roof-footprint threshold with additional conditions.
- City of Portland — Garages, Sheds and Accessory Structures Official local guidance showing a 200-square-foot non-habitable accessory-structure threshold and separate zoning considerations.
- Prince William County, Virginia — Detached Accessory Structures Official local guidance covering 256-square-foot permitting thresholds and zoning requirements.
- Washoe County, Nevada — What Requires a Permit? Official example showing small shed exemptions subject to planning setbacks.
Important: This article provides general educational information and is not a property-specific permit or zoning determination. Shed permit exemptions vary by state, municipality, zoning district, project design and property conditions. Local rules can change. Always verify the current requirements with the relevant building or planning department before purchasing, installing or constructing a shed.