Accessory Structures in Tigard, OR: What Residents Actually Need to Know

If you live in Tigard or are thinking about moving there, accessory structures are one of those things you probably won't think about until they affect you directly. Tigard has 4 specific rules on the books covering different aspects of accessory structures, and some of them might surprise you.

Carport Rules

Tigard treats carports as residential accessory structures under the Tigard Community Development Code. Detached accessory structures must maintain a minimum 5-foot setback from side, street side, and rear property lines, with garage and carport vehicle-entry setbacks measured from the door elevation under the standards in Chapter 18.290 (Small Form Residential) Table 18.290.1. Building permits follow the Oregon Residential Specialty Code adopted under ORS 455.020.

Key details: Code Section: CDC Chapter 18.290 (Small Form Residential). Side/Rear Setback: 5 ft minimum (detached accessory). Vehicle Entry Setback: Per Table 18.290.1. Building Code: Oregon Residential Specialty Code (ORS 455.020). Planning Contact: 503-718-2421.

Constructing a carport without a building permit, or placing one in violation of the CDC 18.290 setback or the underlying zone's setbacks, may trigger a stop-work order from the Tigard Building Division and code-compliance enforcement under the Tigard Community Development Code. Property owners may be required to remove or relocate the structure, obtain after-the-fact permitting, or pay civil penalties.

ADU Rules

Tigard allows accessory dwelling units under Chapter 18.220 (Accessory Dwelling Units) of the Tigard Community Development Code, with a maximum size of 800 square feet, a maximum height of 25 feet for a detached ADU, one detached ADU per lot, and no city-imposed owner-occupancy or additional off-street parking requirement. The framework implements Oregon's statewide ADU mandate under SB 1051 (2017) and HB 2001 (2019).

Key details: Max ADU Size: 800 sq ft (CDC 18.220). Max Detached ADU Height: 25 ft. ADUs Per Lot: 1 detached. Owner Occupancy: Not required (post-2018). Added Parking: Not required by city.

Building or occupying an ADU without permits, exceeding the 800-square-foot or 25-foot size and height limits in CDC Chapter 18.220, or installing more than one detached ADU per lot, may trigger a stop-work order from the Tigard Building Division and code-compliance action under the Community Development Code. Property owners may be required to remove, modify, or obtain after-the-fact permits and may face civil penalties.

Tigard is more permissive than most cities when it comes to adu rules. That said, there are still limits.

Shed Rules

Tigard treats sheds as detached residential accessory structures under the Tigard Community Development Code. Under CDC Chapter 18.290 (Small Form Residential), accessory structures may not be located in the required front-yard setback and must maintain at least a 5-foot setback from side, street side, and rear property lines. Accessory structures may not exceed 528 square feet on lots smaller than 2.5 acres and may not cause the lot to exceed the base-zone lot-coverage maximum.

Key details: Side/Rear Setback: 5 ft minimum (CDC 18.290). Front Yard: Prohibited in required front setback. Max Size (<2.5 ac): 528 sq ft. Max Size (>=2.5 ac): 1,000 sq ft. Building Permit Threshold: Per Oregon Residential Specialty Code.

Placing a shed in the required front-yard setback, closer than five feet to a side, street side, or rear property line, or exceeding the 528-square-foot accessory-structure size cap, is a violation of CDC Chapter 18.290 and enforceable by Tigard Code Compliance. Constructing a shed without required building, electrical, plumbing, or mechanical permits is enforceable by the Tigard Building Division through stop-work orders, after-the-fact permitting, and civil penalties.

Garage Conversions

Tigard allows existing detached garages and other accessory structures to be converted into accessory dwelling units under Tigard Community Development Code Chapter 18.220 (Accessory Dwelling Units), subject to the 800-square-foot size cap, 25-foot height cap, and small form residential setback and lot-coverage rules in Chapter 18.290. Conversions to general habitable space follow the Oregon Residential Specialty Code adopted under ORS 455.020 and require building, electrical, plumbing, and mechanical permits from the Tigard Building Division.

Key details: Authority: CDC Ch. 18.220 (ADUs). Max Size: 800 sq ft (entire structure). Max Height: 25 ft. Setbacks/Coverage: Per CDC Ch. 18.290 base zone. Permits: Building, electrical, plumbing, mechanical.

Converting a garage into habitable space or an ADU without the required Tigard Building Division permits is enforceable by stop-work order, after-the-fact permitting, and civil penalties under the Oregon Residential Specialty Code and TMC Title 14 (Buildings and Construction). Exceeding the 800-square-foot ADU size limit, placing the converted ADU in a required setback, or installing more than one detached ADU per lot, is enforceable as a Community Development Code violation under CDC Chapters 18.220 and 18.290.

The rules around garage conversions in Tigard lean permissive, but that does not mean anything goes.

The Bottom Line

Compared to many U.S. cities, Tigard gives residents more room on accessory structures. 2 of the 4 rules here are rated permissive. But permissive does not mean unregulated. There are still requirements, and the city does enforce them when violations are reported.

Keep in mind that Tigard can amend these rules at any council meeting. For the most current version of any rule mentioned here, check the specific ordinance page, where we track updates as they happen.