14 Best ADU Builders in Oregon – 2026

In Oregon, ADU eligibility can hinge on a property boundary that is easy to overlook: the urban growth boundary. Properties inside it generally benefit from the state’s urban ADU protections, including no owner-occupancy mandate and no added off-street parking requirement. Outside that boundary, a different set of rules applies, with separate acreage thresholds and siting standards. Before comparing builders or floor plans, homeowners should first determine which regulatory framework governs their parcel.

For those who want residential real estate exposure without managing an ADU build, Ark7 offers fractional interests in professionally managed rental-property series. Shares may start as low as $20, depending on offering availability and investor eligibility.

This guide covers 14 ADU builders serving Oregon, along with one municipal planning resource, based on publicly available company information reviewed in 2026. Because pricing, license status, customer ratings, and business addresses can change, verify every contractor through the Oregon Construction Contractors Board and confirm current details before signing an agreement.

Key Takeaways

• Oregon law requires qualifying cities and counties to allow ADUs in certain urban residential areas, subject to state and local siting and design rules. Rural properties are governed by separate requirements.
• For ADUs covered by Oregon’s urban ADU law, local governments generally may not require owner occupancy or additional off-street parking. Different rules can apply to vacation occupancies and rural properties.
• Oregon’s 2019 DLCD model-code guidance suggested that local governments consider size limits in the 800 to 900 square foot range, or 75% to 85% of the primary dwelling. Actual limits vary by jurisdiction.
• Portland’s current standard maximum ADU size is 75% of the primary dwelling’s living area or 800 square feet, whichever is smaller.
• Rural ADUs governed by ORS 215.495 carry a 900 square foot usable-floor-area limit along with a minimum parcel size and other conditions.
• Portland may waive otherwise-applicable ADU System Development Charges in exchange for a recorded 10-year covenant prohibiting accessory short-term rental use.
• Ark7 offers shares in rental-property series starting as low as $20, subject to offering availability and eligibility.

How This List Was Compiled

This list was assembled from publicly available company information rather than a scoring model, and no ranking is implied by the order below. Companies are grouped by region, with one municipal planning resource listed separately because it is not a builder. Licensing, pricing, and experience claims are company-reported where noted, and at least one published CCB number in this market appears to have lapsed. Verify every license directly in the Oregon CCB database and record the date you checked before contracting.

Oregon ADU Rules to Understand First

• Urban framework: Senate Bill 1051 created an ADU requirement for cities over 2,500 population in 2017, later modified by House Bill 2001. Qualifying cities and counties must allow ADUs in certain urban residential areas.
• Owner-occupancy and parking: HB 2001 barred covered local ADU regulations from imposing owner-occupancy or additional off-street parking requirements. These protections apply to ADUs within urban growth boundaries.
• Vacation occupancies: Oregon law expressly allows local regulation of vacation occupancies, so short-term rental use can be treated differently.
• Rural framework: Rural residential ADUs are governed by ORS 215.495, with substantially different conditions including a minimum parcel size and additional eligibility requirements.
• Size: Limits vary by jurisdiction. The 800 to 900 square foot figures circulating online come from 2019 DLCD model-code guidance, which offered suggested ranges for local codes rather than a statewide maximum.
• Portland SDCs: Portland operates an SDC waiver program for ADUs that accept a recorded 10-year covenant restricting accessory short-term rental use. The waiver’s value depends on the charges applicable to your project under current bureau schedules.

14 Oregon ADU Companies and 1 Planning Resource for 2026

1. SQFT Studios (ADU-Exclusive Design-Build)

Location: 1018 SE 8th Ave, Portland, OR 97214

Phone: (503) 515-3834

License: CCB #209382, Architecture Firm ORBAE #ARF-1294

Price Range: Premium ($$$$)

Service Area: Portland metro, select projects statewide

A design-build firm working exclusively on ADUs, established in 2015 by architect Eli Green. The company has earned multiple Best of Houzz awards and maintains both contractor and architecture licenses.

What Sets SQFT Studios Apart:

• Dual contractor and architecture licensure
• Detached backyard ADUs from 288 to 800+ square feet
• Garage conversions and attached ADUs
• Prefabricated modular ADU models

2. COOPER Design Build (Historic Home Integration)

Location: 4560 SW 96th Ave, Beaverton, OR 97005

Phone: (503) 282-0545

Rating: Company-reported 4.9/5 across 30 to 36 reviews

Price Range: Mid to high-end ($$$ to $$$$)

Service Area: Portland metro including Beaverton, Lake Oswego, West Linn, Cedar Mill

With more than 30 years in business, COOPER specializes in integrating ADUs with historic homes and luxury properties.

What Sets It Apart:

• Historic home ADU integration
• Basement and attic ADU conversions
• Custom freestanding ADUs and guesthouses

3. ADU Design & Build (Single-Contract Model)

License: CCB #216926

Price Range: Mid-range ($$ to $$$)

Service Area: Portland metro area

One of the few Portland firms limiting its work almost entirely to accessory dwelling units. Confirm the company’s current business address directly, as public listings conflict.

What Sets It Apart:

• Detached ADUs as the primary focus
• Design-build single contract approach
• Backyard cottages and small infill units

4. Catalyst Construction (Conversion Specialist)

Location: 825 NE 20th Ave, Suite A, Portland, OR 97232

License: CCB #201387

Price Range: Mid-range ($$ to $$$)

Service Area: Portland metro area

Owner-operated by Ryan Klobas with more than 20 years of Portland metro experience.

What Sets It Apart:

• Basement-to-ADU and garage conversions
• Standalone detached units
• Single-contract design-build process

5. Relevant Buildings (Shipping Container ADUs)

Phone: (503) 308-0191

Price Range: Mid-range ($$ to $$$)

Service Area: Oregon and Washington

Relevant Buildings specializes in shipping container ADUs and provides support from design through completion, including financing assistance.

What Sets It Apart:

• Container ADUs as the primary specialty
• Prefab modular and wood-framed options
• Eco-friendly sustainable builds
• Relatively predictable unit costs, though site work still varies

6. Backyard Blueprint (Western Suburbs)

Location: 1544 SE 41st Loop, Hillsboro, OR 97123

Phone: (503) 278-3780

Price Range: Mid-range ($$ to $$$)

Service Area: Hillsboro and western Portland suburbs

What Sets It Apart:

• Concentration in the western Portland suburbs
• ADU design and construction focus
• The company maintains a BBB profile; note that BBB’s current profile states the business is not BBB accredited

7. Neil Kelly Company (Multi-Market Legacy Firm)

Portland Location: 804 N Alberta St, Portland, OR 97217

Beaverton Location: 7721 SW Cirrus Dr, Beaverton, OR 97008

Price Range: Premium ($$$ to $$$$)

Service Area: Portland metro, Eugene, Bend, and Seattle

Founded in 1947, Neil Kelly is one of the Pacific Northwest’s most established design-build firms and a Certified B Corporation, with in-house custom millwork. Its Bend design center brings the same ADU services to Central Oregon.

What Sets It Apart:

• Full ADU design-build services across four markets
• Historic Resource Review expertise
• Solar and energy upgrades
• In-house custom millwork

8. The Powell Group (Portland Portfolio)

Phone: (503) 919-0314

License: CCB #223804

Price Range: Mid-range ($$ to $$$)

Service Area: Greater Portland metropolitan area

With more than 20 years of experience, The Powell Group maintains an ADU portfolio with completed projects across Portland’s SE and SW neighborhoods.

What Sets It Apart:

• Documented Portland neighborhood project history
• Owner-led approach
• Custom home construction alongside ADU work

9. EcoCraft PDX (Energy Efficiency Focus)

Phone: (503) 756-6468

License: Oregon CCB #196501

Price Range: Mid-range ($$ to $$$)

Service Area: Portland and Vancouver

What Sets It Apart:

• Sustainability focus in ADU construction
• Energy-efficient design emphasis
• Full-service design, permits, and build
• Dual-state Portland and Vancouver coverage

10. Portland ADU (Restoration Background)

Service Area: Portland metro, particularly NE Portland

Founded in 2006. Allen’s biography says he developed his craft while working in Germany under a Master Carpenter of the Guild, and he previously focused on historic home restoration before shifting to ADU work. Confirm the company’s current business address directly, as public listings conflict.

What Sets It Apart:

• Historic home restoration background
• Contemporary ADU remodels
• Basement and backyard ADUs
• Straw bale construction experience

11. All Building Construction (Willamette Valley)

Location: McMinnville area, Yamhill County

Owner: Mark Prine

License: The company states Prine has been licensed in Oregon since 2006

Service Area: Yamhill County and the Willamette Valley including McMinnville and Newberg

What Sets It Apart:

• Owner-operated with direct oversight from consultation through final walkthrough
• Home additions alongside ADU construction
• Rural and small-city Willamette Valley coverage

12. WillisBilt / Central Oregon ADU (Bend Specialist)

Location: PO Box 2176, Bend, OR 97709

Phone: (541) 408-0637

License: The company lists CCB #203478. A current CCB-data lookup reports that license expired July 2, 2026. Verify status directly in the Oregon CCB database before engaging.

Price Range: Mid-range ($$ to $$$)

Service Area: Bend, Redmond, and Central Oregon

A Central Oregon ADU specialist operating as a division of WillisBuilt LLC.

What Sets It Apart:

• Central Oregon regional concentration
• Climate-appropriate design for the high desert
• Bend and Redmond coverage

13. Zook Cabins (Factory-Built, Shipped to Oregon)

Factory Location: 5181 Lincoln Hwy, Gap, PA 17527

Phone: (610) 593-4556

Price Range: Mid-range plus delivery and site prep ($$ to $$$)

Service Area: Ships to Oregon with local setup coordination

Zook’s Oregon-marketed ADU models range from about 564 to 848 square feet. Owners must confirm that a selected model complies with the applicable city or county size limits, since there is no universal statewide ADU maximum for urban ADUs.

What Sets It Apart:

• A-Frame dwellings in one and two bedroom configurations
• Grove, Luna, and Sonoma ADU models
• A local contractor is required for foundation work and final utility connections

14. Len’s Home Center (Manufactured Homes as ADUs)

Service Type: Manufactured home retailer and general contractor

Len’s handles floor plan selection through installation and publishes Oregon manufactured-home guidance noting that manufactured homes may qualify as ADUs when HUD and local requirements are met. Confirm the company’s current service area directly.

What Sets It Apart:

• Manufactured homes as ADUs, HUD-code compliant
• Modular homes and park model units
• Permitting assistance
• Some jurisdictions impose additional conditions: Marion County, for example, requires a manufactured home used as an ADU to be ENERGY STAR certified and to bear the HUD certification label

Planning Resource

15. City of Salem Pre-Approved ADU Plans

Location: 555 Liberty St SE, Room 320, Salem, OR 97301

Phone: (503) 588-6256

Type: Municipal Resource, Not a Builder

Salem provides ready-build detached ADU plans for units under 600 square feet and says the program can expedite permitting. Plans are available to both owner-builders and contractors working within Salem city limits.

How to Choose the Right ADU Builder

• By region: Portland metro is served by SQFT, COOPER, ADU Design & Build, Catalyst, Relevant Buildings, Backyard Blueprint, Neil Kelly, Powell, EcoCraft, and Portland ADU; the Willamette Valley by All Building Construction; Central Oregon by WillisBilt and Neil Kelly’s Bend center; and statewide by Zook and Len’s.
• By construction system: Container, prefab, modular, manufactured, and site-built approaches all appear here, and each carries different permitting and appraisal implications.
• By whether you want a plan or a partner: Salem’s ready-build plans suit owner-builders, while turnkey design-build firms suit owners who want one contract.
• By price tier: Premium custom work sits with SQFT and Neil Kelly, mid-range with ADU Design & Build, Catalyst, Powell, and EcoCraft, and value-focused options with the manufactured and prefab providers.

Questions to Ask Any Oregon ADU Builder

• Is my property inside an urban growth boundary, and which statutory framework applies?
• What size limit does my specific jurisdiction set, rather than the DLCD guidance range?
• Is your CCB license active today, and what date did you last confirm it?
• For a rural parcel, does my property meet the ORS 215.495 acreage and siting conditions?
• Does your quote include foundation, utility connections, and permitting, or are those separate?
• Do you perform construction, or coordinate a separate licensed contractor?

Financing an ADU in Oregon

• Home equity options: HELOCs and home equity loans draw on existing equity.
• Cash-out refinance: Accesses equity through a new mortgage, though replacing a low-rate loan can raise total borrowing costs.
• Construction loans: Convert to permanent mortgages at completion.
• Builder-assisted financing: Some builders, including Relevant Buildings, offer financing assistance.
• Portland SDC waiver: Portland may waive otherwise-applicable ADU System Development Charges in exchange for a recorded 10-year covenant prohibiting accessory short-term rental use. The value depends on the charges applicable to your project under current bureau schedules, which were updated for FY 2026 to 2027, so request a project-specific calculation.
• Cost planning: Nonauthoritative planning estimates place detached new-build ADUs at $180,000 to $430,000, garage conversions at $90,000 to $240,000, basement or interior conversions at $100,000 to $230,000, attached additions at $160,000 to $320,000, and prefab or modular installed at $170,000 to $340,000.

Comparing ADUs and Fractional Real Estate

Building an ADU can create rental-income potential and may increase a property’s value, though economics vary substantially based on construction cost, financing, occupancy, operating expenses, taxes, rents, and local restrictions.

ADU considerations:

• Build your projection from current comparable listings in your specific neighborhood rather than a general range.
• Treat any property-value effect as something a local appraiser confirms rather than a percentage you assume.
• If short-term rental use is part of your plan, note that Oregon law expressly allows local regulation of vacation occupancies, and Portland’s SDC waiver requires a covenant prohibiting that use for a decade.
• Any rent-to-cost figure should be stated as an illustrative gross estimate, calculated as annual rent divided by total project cost before expenses, not as a return on investment.
• Rural projects carry additional statutory conditions that can affect both feasibility and cost.

How fractional investing compares:

For those who prefer fractional real estate exposure rather than developing and managing an ADU directly, Ark7 is another model to consider:

• Shares in rental-property series starting at $20 per share, subject to offering availability and eligibility
• Cash distributions when available, subject to property performance, expenses, reserves, and offering terms
• Professional property selection and management
• Exposure across multiple markets rather than a single Oregon property
• No construction timelines or permitting to manage
• Potential access to secondary trading, subject to holding periods, legal and state restrictions, platform availability, and market liquidity. Liquidity is not guaranteed.
• Ark7 IRA options support Traditional and Roth accounts, subject to IRA rules, custodian fees, and individual circumstances

These are speculative securities involving substantial risk, including illiquidity, lack of diversification, and complete loss of capital.

Conclusion

Oregon’s ADU rules are genuinely more permissive than most states’, but the protections that get quoted most often, no owner-occupancy and no added parking, apply to ADUs covered by the urban statute rather than to every property in the state. Rural parcels operate under a separate framework with its own acreage and siting conditions.

Why Oregon Stands Out for ADU Projects

• State-level requirement: Qualifying cities and counties must allow ADUs in certain urban residential areas.
• Owner-occupancy protections: Covered urban ADUs generally cannot be conditioned on owner occupancy.
• Parking protections: Covered urban ADUs generally cannot be conditioned on additional off-street parking.
• Municipal plan programs: Salem publishes ready-build plans for units under 600 square feet.
• Portland SDC waiver: Available in exchange for a recorded 10-year short-term rental covenant.

Investor Tips for Oregon ADU Projects

Establish first whether your property sits inside an urban growth boundary, because that single fact determines which statutory framework applies and whether the owner-occupancy and parking protections reach you at all. Confirm your jurisdiction’s actual size limit rather than relying on the 800 to 900 square foot figures circulating online, which came from suggested model-code guidance. Check every CCB license number directly in the state database and note the date, since at least one number published by a company in this market appears to have lapsed. Request a project-specific SDC calculation from Portland rather than budgeting from a headline waiver figure.

For those who prefer residential real estate exposure without a construction project, Ark7 offers shares in rental-property series starting at $20, subject to offering availability and eligibility.

Frequently Asked Questions

Do Oregon’s ADU protections apply to rural property?

Not in the same way. HB 2001’s owner-occupancy and parking protections concern ADUs within urban growth boundaries. Rural residential ADUs are governed by a separate statute, ORS 215.495, with substantially different conditions including a minimum parcel size and additional eligibility requirements covering matters such as wastewater and fire protection. Rural ADUs are not simply a more permissive version of the urban rules, so confirm which framework applies before planning.

What size ADU can I build in Oregon?

Size limits are set locally rather than by a single statewide maximum. The 800 to 900 square foot figures often cited come from Oregon’s 2019 DLCD model-code guidance, which suggested ranges for local governments to consider. Portland’s current standard maximum is 75% of the primary dwelling’s living area or 800 square feet, whichever is smaller. Rural ADUs governed by ORS 215.495 carry a 900 square foot usable-floor-area limit along with other conditions. Confirm your jurisdiction’s limit before selecting a model or plan.

How do I verify an Oregon contractor’s license?

Search the Oregon Construction Contractors Board database by license number or business name, confirm active status, and record the date you checked. This matters more than usual in this market: at least one company profiled here publishes a CCB number that a current data lookup reports as expired. A number printed on a company website is a starting point, not proof of current standing.

What is the catch with Portland’s SDC waiver?

The waiver requires a recorded 10-year covenant prohibiting accessory short-term rental use of the ADU. That is a decade-long restriction on the property, so it directly conflicts with any plan built around nightly rental income. Portland may waive otherwise-applicable ADU System Development Charges in exchange, and the dollar value depends on the charges applicable to your project under current bureau schedules rather than a fixed figure.

Are manufactured homes allowed as ADUs in Oregon?

Many Oregon jurisdictions permit HUD-code manufactured homes as ADUs, though requirements vary and some jurisdictions impose additional conditions. Marion County, for example, requires a manufactured home used as an ADU to be ENERGY STAR certified and to display the HUD certification label. Verify with your local building department before purchasing a unit, and note that rural parcels face the separate statutory framework described above.

Neither Ark7 nor Ark7 Properties is a broker-dealer or an investment adviser. Dalmore Group LLC, a registered broker-dealer and member FINRA/SIPC, located at 525 Green Place, Woodmere, NY 11598, is the broker-dealer of record for Ark7, an issuer direct offering. Neither Ark7 nor Dalmore makes recommendations or provides advice about investments, and nothing here should be construed as a recommendation for any security. An investment in an offering constitutes an investment in a particular series and not in Ark7 or any of the underlying assets. Investments on the Ark7 platform are speculative and involve substantial risks, including illiquidity, lack of diversification, and complete loss of capital. Cash distributions are not guaranteed and are subject to property performance, expenses, reserves, and offering terms. Past performance is no guarantee of future results. This article is for informational purposes only.