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

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

Garage Conversions

Garage conversions to ADUs are permitted in Beaverton. Existing legal non-conforming structures can be converted to ADUs provided the conversion does not increase the non-conformity. Building, mechanical, plumbing, and electrical permits are required. The converted unit must have a separate exterior entrance and meet all ADU standards.

Key details: Permitted: Yes — garage-to-ADU conversions allowed. Non-Conforming: Conversion allowed if it does not increase non-conformity. Permits Required: Building, mechanical, plumbing, electrical. Separate Entrance: Required — no inter-communicating doors with primary dwelling. Size Limit: 800 sq ft maximum for detached ADU.

Unpermitted conversion: building code enforcement. Must bring to code or restore. Safety violations: immediate correction.

Carport Rules

Beaverton regulates carports as residential accessory structures under the Beaverton Development Code Chapter 60 (Special Requirements), Section 60.50 (Accessory Dwelling Units and Residential Accessory Structures). Carports must meet the same yard setbacks as the principal dwelling under the underlying residential zone in BDC Chapter 20, and garage door or vehicle-entry setbacks are measured from the door elevation to the property line. Building permits are administered under BMC Chapter 8.02, which adopts the Oregon Residential Specialty Code.

Key details: Governing Code: Beaverton Development Code Chapter 60. Setback Rule: Same as principal dwelling (per underlying zone). Garage Door Measurement: From door elevation to property line. Building Code: Oregon Residential Specialty Code (ORS 455.020). Permit Authority: Beaverton Building Division (BC Chapter 8.02).

Constructing a carport without a building permit, or placing one in violation of BDC Section 60.50 setbacks or the underlying zone's setbacks, may trigger a stop-work order from the Beaverton Building Division and code-compliance enforcement under the Beaverton Development Code. Property owners may be required to remove or relocate the structure, obtain after-the-fact permitting, or pay civil penalties.

Shed Rules

Sheds and detached accessory structures in Beaverton are regulated by the Beaverton Development Code Chapter 60 (Section 60.50, Residential Accessory Structures) and the Oregon Residential Specialty Code adopted under BC Chapter 8.02. One-story detached accessory structures of 200 square feet or less are generally exempt from a building permit under the Oregon Residential Specialty Code, but they must still comply with the setbacks of the underlying residential zone (BDC Chapter 20). Sheds cannot be used as habitable dwelling units unless converted into an ADU with full permitting.

Key details: Permit Exemption: 1-story sheds <=200 sq ft (Oregon Residential Specialty Code). Setbacks: Per underlying residential zone (BDC Chapter 20). Code: BDC Section 60.50; Beaverton Code Chapter 8.02. Lot Coverage: Counts toward zone's maximum (typically 40-50%). Habitation: Not allowed unless converted to permitted ADU.

Installing a shed in violation of zoning setbacks or lot coverage, or constructing a permit-required shed without permits, may trigger code-compliance enforcement under the Beaverton Development Code. Remedies include after-the-fact permitting, relocation, or removal, plus civil penalties. Habitable use of a non-permitted shed is treated as an unlawful dwelling unit.

ADU Rules

Beaverton allows one ADU per detached dwelling unit in all residential zones under Development Code Chapters 40 and 60. Detached ADUs are limited to 800 sq ft; attached ADUs cannot exceed 50% of primary dwelling or 800 sq ft. Detached ADU height limit is generally 16 feet. No owner-occupancy requirement. No parking minimum near transit per state law.

Key details: Allowed: One ADU per detached dwelling in all residential zones. Detached ADU Max: 800 sq ft, 16 feet height. Attached ADU Max: 50% of primary dwelling or 800 sq ft (whichever less). Owner Occupancy: Not required (Oregon state law). Parking: No minimum near transit (HB 2001).

Unpermitted ADU construction: stop-work order and retroactive permit fees. Occupancy without final inspection: red-tagged until corrected.

The Bottom Line

Beaverton'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 Beaverton is broadly strict or permissive.

These rules come from Beaverton's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.