Accessory Structures in Fort Smith, AR: What Residents Actually Need to Know

If you live in Fort Smith or are thinking about moving there, accessory structures are one of those things you probably won't think about until they affect you directly. Fort Smith has 5 specific rules on the books covering different aspects of accessory structures, and some of them might surprise you.

Shed Rules

Sheds and similar accessory structures in Fort Smith are regulated through two layers: (1) the Fort Smith Unified Development Ordinance, which sets dimensional standards by district (size, height, setbacks, lot coverage, location relative to the principal dwelling); and (2) the locally adopted International Residential Code, which under IRC R105.2 typically exempts one-story detached accessory structures of 200 square feet or less from building permit requirements but does not waive zoning compliance. Fort Smith property owners generally need a zoning permit from the Department of Development Services even when no building permit is required. The Fort Smith Code is hosted on Municode at https://library.municode.com/ar/fort_smith.

Key details: IRC Permit Exemption: ≤200 sq ft (IRC R105.2). Zoning Permit: Generally still required. Typical Location: Rear yard, behind front building line. Setbacks: Set by district (commonly 3-5 ft). Floodplain Review: Required near Arkansas River.

Installing a shed without a required zoning permit violates the Fort Smith UDO, enforceable through notices of violation, cease-and-desist orders, and civil action in Sebastian County Circuit Court under A.C.A. §14-56-417. Unpermitted sheds in setbacks or exceeding lot coverage may be ordered removed. Sheds over the 200-square-foot IRC R105.2 threshold built without a building permit additionally violate the locally adopted IRC and trigger stop-work orders. Floodplain violations expose the city and owner to FEMA NFIP compliance issues.

Garage Conversions

Converting a Fort Smith garage into habitable space (a bedroom, in-law suite, home office, or ADU) requires both (1) zoning approval under the Fort Smith Unified Development Ordinance for the change of use, since the converted area no longer functions as accessory parking and may trigger off-street parking minimums or ADU classification; and (2) a building permit under the locally adopted International Residential Code. Conversions must meet IRC Chapter 3 requirements for habitable spaces including R310 emergency egress, R305 ceiling height, R314 smoke alarms, and R315 carbon monoxide alarms, and the UDO's off-street parking minimums must still be satisfied after the garage is removed.

Key details: Building Code: Locally adopted IRC. Egress Standard: IRC R310 (5.7 sq ft minimum). Ceiling Height: IRC R305 (7 ft habitable rooms). Smoke/CO Alarms: IRC R314 / R315. Zoning Review: Change-of-use approval required.

Performing a garage conversion without permits violates the locally adopted IRC (A.C.A. §14-54-1604 building permit authority) and the Fort Smith UDO. Enforcement includes stop-work orders, requirement to undo the conversion or obtain after-the-fact permits with elevated fees, and civil action under A.C.A. §14-56-417. Unpermitted habitable conversions that fail to meet IRC R310 egress are commonly cited in fire-injury cases and may expose the owner to liability. Properties with reduced parking below the UDO minimum may also be cited.

ADU Permits

An accessory dwelling unit in Fort Smith requires permits from two municipal tracks: a zoning permit or special use permit through the Department of Development Services confirming the ADU is permitted in the district under the Fort Smith Unified Development Ordinance, and a building permit from the Fort Smith Building Official under the locally adopted International Residential Code for the construction itself. Arkansas has no statewide ADU preemption like California's SB 9 or Oregon's HB 2001, so timelines, fees, hearing requirements, and approval criteria are set entirely by Fort Smith pursuant to A.C.A. §14-56-401 et seq. and applicable local ordinances.

Key details: Permit Tracks: Zoning + Building (both required). Zoning Authority: Fort Smith Development Services. Hearings (Special Use): Fort Smith Planning Commission. Variances: Board of Zoning Adjustment. Enabling Statute: A.C.A. §14-56-401+.

Constructing an ADU without permits violates the locally adopted IRC and the Fort Smith UDO. Enforcement is through notice of violation, cease-and-desist orders, civil action in Sebastian County Circuit Court under A.C.A. §14-56-417, and stop-work orders from the Building Official. After-the-fact permits typically carry doubled fees and require the applicant to demonstrate code compliance through invasive inspections. Unpermitted occupancy without a Certificate of Occupancy is also a violation enforceable by Code Enforcement.

ADU Rules

Fort Smith is a first-class city in Sebastian County, Arkansas (population approximately 89,000), regulating accessory dwelling units through its Unified Development Ordinance adopted in 2011. Arkansas has no statewide ADU preemption statute equivalent to California Government Code §66313 or Oregon ORS 197.312, so whether an ADU is permitted in Fort Smith is determined entirely by the local UDO under planning and zoning authority granted to Arkansas cities by A.C.A. §14-56-401 et seq. The UDO classifies dwelling units by district, and ADU permissibility (whether by right, by special use permit through the Planning Commission, or prohibited) depends on the underlying residential zone. The Fort Smith Code on Municode is the controlling local source: https://library.municode.com/ar/fort_smith.

Key details: State ADU Preemption: None (locally controlled). Local Authority: Fort Smith UDO (2011). Enabling Statute: A.C.A. §14-56-401+. Review Body: Planning Commission / BZA. Building Code: Locally adopted IRC.

Constructing or occupying an unpermitted ADU in Fort Smith is a UDO violation enforceable under A.C.A. §14-56-417 (zoning enforcement) and the UDO's enforcement chapter. Fort Smith Development Services issues notices of violation and may seek civil penalties, injunctive relief in Sebastian County Circuit Court, and removal of unpermitted structures. Unpermitted construction additionally violates A.C.A. §14-54-1604 (building permit authority) and the locally adopted IRC, triggering stop-work orders from the Fort Smith Building Official. Continuing violations are treated as separate offenses for fine purposes.

ADU Impact Fees

Arkansas has not enacted a statewide impact fee enabling statute, and Arkansas cities have historically had limited authority to impose development impact fees outside of negotiated agreements. Fort Smith does not impose general development impact fees on residential construction; ADU applicants typically face only standard zoning permit fees, building permit fees under the locally adopted IRC, and utility connection (tap) fees through Fort Smith Utilities (water and sewer) and the appropriate gas and electric utilities. School districts in Arkansas have no impact-fee authority. Recreation, traffic, and park impact fees are not generally assessed by Fort Smith on infill ADU construction.

Key details: AR Impact Fee Authority: No general statute. Fort Smith Impact Fees: Not imposed on ADUs. Permit Fees: Zoning + Building (set by ordinance). Utility Tap Fees: Through Fort Smith Utilities. School Impact Fees: Not authorized in AR.

Failure to pay required permit and tap fees prevents permit issuance and Certificate of Occupancy. Cities that attempt to collect unauthorized impact fees outside statutory authority face challenge under Arkansas constitutional and statutory limits on municipal exactions; courts have historically scrutinized exactions that lack a clear statutory basis. Fees collected without authority are subject to refund. Failure to obtain water or sewer service through proper channels can result in service termination and unauthorized connection penalties under Fort Smith Utilities tariffs.

The rules around adu impact fees in Fort Smith lean permissive, but that does not mean anything goes.

The Bottom Line

Fort Smith's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Fort Smith is broadly strict or permissive.

This guide is based on Fort Smith's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.