How Big Can You Build Without a Permit? Sheds, Decks, and Fences

Under the model residential code most U.S. jurisdictions follow, you can generally build a one-story detached shed or workshop up to 200 square feet, a freestanding low deck up to 200 square feet, a fence up to 7 feet tall, or a retaining wall up to 4 feet without pulling a building permit. That is the short answer to how big you can build without a permit, and it comes from Section R105.2 of the 2021 International Residential Code (IRC).¹ Local governments amend those numbers downward all the time, and other rules — zoning, HOAs, easements — can block a project that is technically permit-exempt. The size limit is the floor of the analysis, not the whole answer.

Sheds and Detached Accessory Structures

The IRC exempts one-story detached accessory structures with a floor area of 200 square feet or less.¹ That covers storage sheds, workshops, garden buildings, and similar uses. The structure has to be detached from the main house and limited to one story. Add plumbing, permanent electrical wiring, or a mechanical system, and the exemption disappears regardless of how small the building is.

Some areas apply a lower cap. The International Building Code (IBC), used for commercial properties and applied to residential accessory structures in some jurisdictions, sets the exempt size at 120 square feet.² Communities in high-wind zones, flood-prone areas, or heavy-snow regions often push the threshold lower still. Treat 200 square feet as a starting benchmark and confirm the local number before you buy materials.

Decks

A deck skips the permit if it meets all four IRC conditions: the total area is 200 square feet or less, no part of the deck surface sits more than 30 inches above the surrounding grade, the deck is not attached to the house, and it does not serve a door required for emergency exit.¹ Miss any single condition and a permit is required.

Attachment is the condition homeowners run into most. Once you bolt a ledger board to the house, the deck becomes part of the building’s structural system and has to be engineered so it cannot pull away from the wall. A large entertaining deck off a back door will need a permit every time. A small, ground-level platform sitting a few inches off the grass is the project the exemption was written for.

Fences and Retaining Walls

Fences up to 7 feet tall are exempt from a building permit under the IRC.¹ That ceiling applies to wood, vinyl, chain-link, and similar lightweight materials. Masonry walls of brick or stone can trigger permit requirements at lower heights because of their weight and the risk of collapse without proper footings.

Front-yard fences carry a separate limit from zoning, not from the building code. Most areas cap front-yard fences at 4 to 5 feet, and corner lots face additional restrictions inside a sight triangle at the intersection, commonly about 50 feet along each curb, so drivers can see cross traffic. A 4-foot fence can still violate that rule if it sits too close to the corner.

Retaining walls follow a simple threshold: anything 4 feet or shorter, measured from the bottom of the footing to the top of the wall, does not require a permit unless the wall supports an added load like a driveway or a building above it.¹ Walls over 4 feet usually need engineered plans because soil pressure climbs sharply with height. Stacking two short walls to sneak under the threshold is something inspectors watch for, and it rarely works.

Interior Work That Stays Exempt

The IRC exempts painting, wallpapering, tiling, carpeting, cabinet installation, countertop replacement, and similar finish work.¹ Hardware swaps, refinishing floors, and installing shelving fit the same category. None of that changes how the building carries loads, moves water, or distributes electricity.

The line moves the moment you touch a load-bearing wall, reroute plumbing, or run new electrical circuits. Replacing a switch or a faucet is maintenance. Adding a bathroom, moving a kitchen sink to a different wall, or wiring a new circuit is not, and those projects require permits and licensed inspections.

Windows and doors sit in the middle. Swapping glass within an existing frame or adding a storm door over existing fenestration generally stays exempt. Changing the size of an opening, altering an exterior wall, or replacing a window that serves as an emergency escape route can require both a permit and compliance with egress-size standards. A short call to the building department settles most window questions.

What Flips a Small Project Into Permit Territory

Size exemptions vanish the moment you add certain systems. A 100-square-foot shed needs no building permit. Wiring a single outlet inside it does.

Under the IRC, the only electrical work exempt from permits is low-stakes activity: replacing a lamp, plugging equipment into an existing receptacle, or installing decorative lighting that connects by cord and plug.¹ Any new wiring, new circuit, or change to the electrical panel needs a permit. The National Electrical Code, enforced in all 50 states, exists in large part because improperly installed wiring is a leading cause of residential fires.³

Plumbing follows the same logic. Stopping a leak or replacing a faucet is exempt. Running new supply lines, adding a drain, or installing a water heater is not. Gas work is tighter still: only portable gas appliances not connected to fixed piping are exempt. Any connection to a gas line requires a permit and inspection.

Zoning, Setbacks, and Easements

A structure can be small enough to skip the building permit and still violate the local zoning code. Zoning and building permits are separate regulatory layers, and clearing one does not clear the other.

Most jurisdictions cap the height of permit-exempt structures at 10 to 12 feet, measured from average finished grade to the highest point of the roof. Taller structures change wind-load calculations and start casting shadows on neighboring lots, both of which bring extra scrutiny.

Setback rules control how close to a property line you can build. A shed that needs no building permit can still require a variance if you want to place it within, say, 5 feet of the property line. Setback distances vary widely and come from local zoning ordinances, not the building code.

Easements deserve their own look because they are invisible on the ground. A utility easement across the back of your lot gives the utility company the legal right to access, dig up, or run equipment through that strip. Build a shed on top of it and the utility can remove the structure to reach its infrastructure, at your cost. Check your plat or survey for easement lines before you pick a spot.

HOAs, Historic Districts, and Environmental Overlays

Three other layers of regulation can block a project that is otherwise permit-exempt.

Homeowners associations enforce their own covenants, conditions, and restrictions (CC&Rs), and those frequently go further than the municipal code. An HOA can prohibit sheds entirely, require architectural review for any visible structure, or restrict materials and colors. The local building department does not enforce HOA rules, and the HOA cannot issue permits, but violating CC&Rs can bring fines, liens, and forced removal of the structure. Both sets of rules apply independently.

Properties in locally designated historic districts face an added review. Even fully permit-exempt work may still require a Certificate of Appropriateness from the local historic preservation office before any exterior change. The review looks at whether the work fits the district’s character, and it can reach fencing, shed placement, and exterior paint colors. Getting approval after the fact is harder and more expensive than getting it in advance.

Environmental rules can override size-based exemptions. Properties near wetlands, in floodplains, or subject to stormwater management can trigger drainage or environmental review when any new impervious surface is added, even a 100-square-foot concrete pad. Coastal zones, critical habitat areas, and steep-slope properties often carry their own overlay rules that shrink what you can build without government review.

What Happens If You Build Without a Required Permit

Consequences run well past a single fine. Local enforcement agencies can issue a stop-work order that halts construction until the violation is resolved. Daily fines for ignoring a stop-work order typically range from $100 to several thousand dollars depending on the jurisdiction, and they accumulate quickly. In serious cases, the building department can require you to tear down the unpermitted structure or open finished walls so an inspector can verify what’s behind them.

The financial damage often surfaces years later. Unpermitted work must be disclosed when you sell, and buyers, lenders, and appraisers all look for it. A buyer’s inspector who spots an unpermitted addition can derail a sale or force a price reduction. Insurance adds another risk: if damage occurs in connection with unpermitted work, such as an electrical fire in an unpermitted room, an insurer may deny the claim on the grounds that the work was never inspected for code compliance.

Retroactive permits are possible in many areas, but they cost more than the original would have, and they often require exposing framing, wiring, or plumbing already covered by drywall.

How to Confirm Your Local Rules

Model codes set the floor, not the ceiling, for what local governments require. Your municipality or county building department makes the final call, and jurisdictions routinely amend the IRC and IBC thresholds for local conditions like snow load, hurricane risk, wildfire exposure, and flood designation.

Before starting a project that looks exempt on paper:

Check the zoning map on your local planning department’s website or GIS portal for your zoning district, setback rules, lot coverage limits, and any overlays like floodplains or historic districts.
Review your plat or survey for easements, property lines, and building envelopes. A copy is usually on file with the county recorder if you don’t have one.
Call the building department and describe the project. A short conversation is the most reliable way to confirm whether a permit is needed, and many departments answer these questions by email as well.
Read your HOA CC&Rs, particularly the architectural review provisions, if your property is in an association.

The IRC itself carries a reminder worth holding onto: exemption from a permit does not authorize any work that otherwise violates the building code or local ordinances.¹ A project can be small enough to skip the paperwork and still break setbacks, height limits, lot coverage ratios, or environmental rules. Permit-exempt means you don’t file for the building itself. It does not mean the project is unregulated.

1
Grant County, WA. 2021 International Residential Code (IRC) Section R105 Permits
2
City of Ronan. 2012 IBC Exempt
3
National Fire Protection Association. Understanding NFPA 70, National Electrical Code (NEC)