Do I Need a Permit to Build a Shed in Maine?

The MUBEC and How Maine Enforces Building Codes

Maine's building code system has a quirk that sets it apart from most states: enforcement depends on where you live. The Maine Uniform Building and Energy Code (MUBEC) applies to all construction statewide, but only municipalities with a population of 4,000 or more residents are required to enforce it. Smaller towns can voluntarily adopt MUBEC enforcement, and many have, but some rural communities in Maine have no building code enforcement at all.

This doesn't mean you can build whatever you want in a small town. Local land use ordinances, shoreland zoning, floodplain regulations, and setback requirements apply in every municipality regardless of population. It just means there may be no building inspector reviewing your shed's structural details in some parts of the state.

The MUBEC was updated effective April 7, 2025, moving from the 2015 codes to the 2021 IRC for residential construction. Under the current code, one-story detached accessory structures — including storage sheds — with a floor area under 200 square feet are exempt from a building permit. This exemption mirrors the IRC's Section R105.2 and applies in all municipalities that enforce MUBEC.

For a broader look at how shed permits work across the country, see our national guide to shed permits.

What the 200-Square-Foot Exemption Covers

The MUBEC's building permit exemption for sheds under 200 square feet is straightforward in concept but limited in scope. To qualify, the structure must be:

• One story and detached from the dwelling
• Used as a tool shed, storage shed, playhouse, or similar non-habitable use
• Under 200 square feet of floor area
• Without plumbing, electrical, or mechanical connections (these trigger separate trade permits)

The exemption applies only to the building permit. It does not exempt the shed from local zoning requirements, shoreland zoning rules, floodplain regulations, or setback requirements. In practice, most Maine municipalities require you to contact the Code Enforcement Officer before building any structure, even a small shed.

Some towns enforce the exemption strictly. The town of Kennebunk, for example, requires a building permit for all sheds, and sheds over 200 square feet must include construction plans with the application. Wells requires permits for all structures and does not provide an exemption for small sheds. Other towns follow the MUBEC exemption as written.

How Five Major Maine Cities Handle Shed Permits

Portland: Full Permitting with Historic District Considerations

Portland is Maine's largest city and has a well-staffed Permitting and Inspections Department. Portland follows the MUBEC exemption for sheds under 200 square feet, but all construction — including accessory structures — requires land use review to verify zoning compliance.

For sheds over 200 square feet, Portland requires a full building permit with construction plans. Permit fees are valuation-based, calculated on the estimated total cost of construction. The city also has significant historic districts where exterior work may require additional design review, potentially adding time to the process. Properties built before 1940 may face a delay of up to 90 days on demolition or exterior building permits. Portland's review time for straightforward residential projects runs about two to four weeks.

Lewiston: Permits for All Construction Activity

Lewiston requires permits for all construction activity and enforces the MUBEC through its Planning and Code Enforcement department. The city's permit process requires a completed application with required documentation, review by staff, payment of fees, and issuance before any work can begin.

Lewiston's fee structure starts with a base fee around $45 for minor structures, with additional charges tied to project valuation. The city emphasizes that no construction activity may occur until a permit has been paid for and issued. For small sheds under 200 square feet, the process is relatively simple, but you still need to apply and receive approval.

Bangor: Building Department Review Required

Bangor handles building permits through its Code Enforcement Department. The city requires permits for all types of construction including new buildings, additions, alterations, and changes in use. Like other MUBEC-enforcing communities, Bangor follows the 200-square-foot exemption from a building permit for small sheds, but zoning compliance is still required.

Bangor has historic districts that may add an extra layer of review for properties in those areas. The city's permit fees are valuation-based, and review times are typically one to two weeks for straightforward accessory structures.

South Portland and Biddeford: Coastal Considerations

South Portland and Biddeford share a common challenge: significant portions of both cities fall within shoreland zones or flood hazard areas that add permit requirements beyond the standard MUBEC rules.

South Portland's Code Enforcement team handles all permit applications and has moved to an online portal for submissions. The city enforces MUBEC and local zoning, with particular attention to properties near waterways and the coast. Properties built in 1940 or earlier may face an additional demolition delay for exterior work.

Biddeford, situated on the Saco River and the coast, has extensive shoreland zoning areas. A shed that would be permit-exempt in an inland neighborhood may require a full permit with site plan review if the property is within 250 feet of a waterbody.

Shoreland Zoning: Maine's Biggest Shed Permit Wildcard

Maine's Mandatory Shoreland Zoning Act is one of the most significant factors in shed permitting across the state. Every municipality in Maine is required to adopt shoreland zoning ordinances that regulate development within 250 feet of:

• Great ponds (lakes 10 acres or larger)
• Rivers
• Freshwater wetlands (10 acres or larger)
• Coastal wetlands
• Tidal waters

Within the shoreland zone, the rules are stricter than the standard MUBEC. A permit is generally required for any new structure, regardless of size. Additional standards apply:

• Lot coverage limits are often more restrictive
• Vegetation clearing within the buffer may be restricted
• Setbacks from the normal high-water line must be maintained
• Structures in Resource Protection zones may be prohibited entirely

Maine has over 6,000 lakes and ponds, 32,000 miles of rivers and streams, and 3,500 miles of coastline. A large number of residential properties fall within shoreland zones, particularly in popular areas like the Lakes Region, Midcoast, and Downeast. If your property is within 250 feet of any significant waterbody, assume that a permit is required for your shed and plan accordingly.

Small Towns Without Code Enforcement

If you live in a Maine town with fewer than 4,000 residents that has not voluntarily adopted MUBEC enforcement, there may be no building code review for your shed project. But this doesn't mean you have a blank check.

Every Maine municipality has a Code Enforcement Officer (CEO) who handles land use permits and shoreland zoning. Even in towns without building code enforcement, the CEO reviews new construction for compliance with local zoning ordinances, setback requirements, lot coverage limits, and environmental regulations. You still need to submit a site plan and receive approval before building.

The practical difference is that in non-enforcing towns, no one reviews your shed's structural details, framing, or roof design for building code compliance. The responsibility for meeting code requirements falls entirely on you. This can be a significant risk, especially in areas with heavy snow loads or high winds.

Snow Loads and Climate Considerations

Maine's climate demands that even small sheds be built to handle significant snow loads. Ground snow loads across the state range from about 50 pounds per square foot along the southern coast to well over 100 pounds per square foot in northern and mountainous areas. The Aroostook County region and western mountains see some of the heaviest snow loads in the eastern United States.

Pre-built shed manufacturers selling in Maine typically design their roofs for New England snow loads, but not all manufacturers build to the same standard. If you're buying a pre-built shed, confirm that the roof is rated for the snow load in your specific location. If you're building from scratch, the IRC provides tables for calculating the required roof structure based on local snow load, lumber species, and rafter spacing.

Maine's frost depth ranges from about 48 inches in the south to 60 inches or more in northern areas. Permanent foundations should extend below the frost line. Most small sheds avoid this requirement by using temporary foundations — skids, gravel pads, or surface-mounted concrete blocks — that allow the structure to move slightly with freeze-thaw cycles without structural damage.

Pre-Built vs. Site-Built Sheds

Maine treats pre-built and site-built sheds the same way under the building code. If the shed is over 200 square feet, it needs a building permit regardless of whether it was built in a factory or assembled on your property. If it's under 200 square feet, the building permit exemption applies to both types.

Pre-built sheds delivered to your property still need to comply with local zoning rules. The delivery company may handle some aspects of site preparation, but the property owner is responsible for ensuring the shed meets setback requirements, lot coverage limits, and any applicable shoreland zoning restrictions.

One important distinction: manufactured housing as defined in Maine Title 10, Chapter 951, is governed by a separate set of state rules and is exempt from local building codes (though not from zoning). A storage shed is not manufactured housing. If a shed manufacturer tells you their product is exempt from local permits because it's "manufactured," that claim does not apply to sheds.

Foundation and Site Preparation

The type of foundation you choose for your shed affects both code compliance and practical performance in Maine's climate.

Gravel pads are the most common foundation for small to mid-size sheds in Maine. A 4- to 6-inch layer of compacted gravel provides drainage, prevents moisture from wicking into the shed floor, and creates a stable, level surface. Gravel pads don't require below-frost-line footings and are generally treated as temporary foundations.

Concrete blocks or piers placed on the surface provide point support for the shed's floor frame. They work well on level sites but can shift in freeze-thaw conditions. In coastal areas, piers may be preferred because they allow water to flow under the structure during storm events.

Concrete slabs are permanent foundations that may trigger a building permit even for small sheds. In areas with poor drainage or high water tables, a slab provides the most stable and dry foundation but adds significant cost.

In flood zones, the foundation type is especially important. FEMA requires structures in Special Flood Hazard Areas to either be elevated above the Base Flood Elevation or include flood openings that allow water to enter and exit freely. Many coastal and riverfront properties in Maine fall within these zones.

HOA and Covenant Restrictions

Maine is not as heavily governed by Homeowners Associations as Sun Belt states, but HOA communities exist in suburban areas around Portland, Bangor, and other population centers. Coastal and resort communities may also have deed restrictions that limit accessory structures.

Common HOA restrictions on sheds include size limits, material requirements (matching siding and roofing to the main house), color restrictions, and prohibitions on metal buildings. Some communities limit the number of accessory structures per lot or require architectural review committee approval before construction.

Even without an HOA, some Maine properties have deed covenants from subdivisions that restrict the type, size, or placement of outbuildings. Check your deed and any recorded covenants before building.

Consequences of Skipping the Permit

Building a shed without a required permit in Maine carries financial and legal risks:

• Fines ranging from $100 to $2,500 per violation under state law
• Orders to remove the shed if it violates setbacks, shoreland zoning, or other regulations that can't be corrected after the fact
• After-the-fact permit fees that are typically higher than the original permit would have been
• Problems at sale when a title search or home inspection reveals unpermitted structures
• Environmental liability if the shed is in a shoreland zone and violates DEP regulations

The cost of a shed permit in Maine is low — typically $30 to $150 for a small to mid-size structure. The consequences of building without one can be far more expensive.

If you're also planning a garage or carport alongside your shed, note that Maine has separate permit requirements for each structure, and total lot coverage of accessory structures may be capped by your zoning district.

For an overview of all building permit requirements in Maine — including decks, fences, pools, and more — see our complete Maine building permit guide.