Accessory dwelling unit companies

Looking for accessory dwelling unit companies in Portland, OR? Call AccessoryDwellingUnit Services for a contact a provider — no obligation. Licensed adu builders serve Portland and the surrounding area, and you'll get straight answers on timing and what affects the price.

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total investment. The final figure depends heavily on whether you choose a prefab unit or a custom build from the ground up. Site conditions are another major factor; if your property requires extensive grading, utility trenching, or foundation work, costs will climb. You also have to consider your choice of finishes, like high-end appliances or custom cabinetry. Navigating local permit fees and impact assessments also adds to the total.

About this service

These companies provide comprehensive support for homeowners, often pairing design experts with construction crews to handle the entire project under one roof. They are helpful when you want to avoid hiring separate architects and builders. You should look into these companies when you want a streamlined experience and a single point of accountability for your backyard project from start to finish.

Frequently asked in Portland

What are the disadvantages of ADUs?

How much does an ADU cost in Massachusetts?

While this query focuses on Massachusetts, ADU costs in Portland are similarly influenced by several factors. These include the size of the unit, the quality of materials used, and the site's unique challenges. Foundation work, utility hookups, and interior finishes all contribute to the overall expense. The specific neighborhood within Portland can also affect labor and material prices. A personalized quote is the most reliable way to determine your project's cost.

What are the rules for ADUs in California?

California has state-level regulations that simplify ADU development, though local zoning can still apply. Common rules involve minimum lot sizes and setbacks from property lines. There are also often requirements for owner-occupancy and parking. While this is about California, your focus should be on Portland's specific regulations.

Is ADU allowed in Maryland?

Yes, ADUs are permitted in many areas of Maryland, with regulations varying by county and municipality. Maryland has been proactive in promoting ADUs to address housing needs. Though this isn't directly related to Portland, it indicates a growing acceptance of ADUs nationwide.

These initiatives are designed to lower the upfront financial barrier to building an ADU. While this is a California program, it shows a trend toward financial incentives for ADUs. When you call for your Portland quote, ask about any available local or state programs.

What are the rules for ADU in California?

California's ADU laws are structured to encourage their construction by limiting local hurdles. Typical regulations include restrictions on ADU size and mandates for fire sprinklers. Many jurisdictions also have specific guidelines for utility connections and parking. Understanding these rules is vital for any ADU project, but you must follow Portland's specific ordinances.

Also serving nearby: Vancouver · Beaverton · Gresham · Hillsboro · Salem

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More on this: HUD ADU resources — ADU policy and financing research.

Service area details

630,498residents

4,723per sq mile

8ZIP codes served

Serving all of Portland — population 630,498; about 4,723 residents per square mile across 133.5 sq mi. ZIP codes covered include 97201, 97202, 97203, 97204, 97205, 97206, 97207, 97208.

Neighborhoods served in Portland: Alberta Arts District, Sellwood-Moreland, Laurelhurst, Hawthorne District, Mississippi Avenue, Pearl District — and every surrounding area.