Best Accessory Dwelling Unit in Portland, OR | AccessoryDwellingUnit Experts

Looking for best accessory dwelling unit in Portland, OR? Call AccessoryDwellingUnit Experts 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 is a major project, and the final bill depends on a few key things. Site prep is a big factor; if your land is sloped or needs extensive utility connections, costs go up. The materials you choose—from siding to kitchen finishes—also change the math significantly. Whether you’re building a detached unit or converting an existing garage shifts the permit requirements and structural work needed. We provide exact pricing confirmed free on the call.

About this service

The best ADU is one that is built to last and fits perfectly into your existing property layout while meeting all local regulations. You need a high-quality unit if you are looking to increase your property value or create a comfortable long-term space for guests or tenants. We focus on durable construction and thoughtful layouts that maximize every square foot of your backyard. Exact pricing confirmed free on the call.

Frequently asked in Portland

What are the best ADU services in Portland?

What is an ADU unit in Portland?

An ADU unit in Portland is a secondary housing dwelling on a single-family lot, such as a backyard cottage, basement apartment, or garage conversion. They provide additional living space or rental income. Portland has specific regulations for ADUs. We can help you find local pros who know these rules. Call for a quote.

What is the best ADU for my property in Portland?

Who is a good ADU builder in Portland?

What does accessory dwelling unit mean in Portland?

In Portland, accessory dwelling unit (ADU) refers to a secondary housing unit on a single-family residential lot. This could be attached to the main house or a separate structure. ADUs are intended to provide independent living quarters. We can help you find local experts to discuss your ADU project. Call for a quote.

What is the accessory dwelling unit permit cost in Portland?

What is the cost of an accessory dwelling unit in Portland?

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: Pearl District, Nob Hill, Hawthorne District, Alberta Arts District, Sellwood-Moreland — and every surrounding area.