What does accessory dwelling unit mean

Looking for what does accessory dwelling unit mean 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

An accessory dwelling unit is a secondary house or apartment that shares the building lot of a larger, primary home. It is a flexible housing solution used for aging parents, adult children, or generating rental income. The term covers everything from garage conversions to new detached cottages. Understanding this definition helps you determine if your property has the potential to add living space. Exact pricing confirmed free on the call.

Frequently asked in Portland

How do I get an ADU estimate in Portland?

What are some examples of homes with mother-in-law suites in Portland?

Homes with mother-in-law suites in Portland often feature detached backyard cottages or attached basement or garage conversions. These spaces are designed for independent living while remaining connected to the main house. The specifics vary greatly based on the original home's structure and lot size. Professionals can help design the right fit.

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

The typical cost of an accessory dwelling unit in Portland varies widely. Factors include the size, the quality of materials, and any site-specific challenges like complex foundations or utility hookups. A professional quote is the most accurate way to determine the financial scope for your project.

How do I get an ADU quote for my property in Portland?

What are the requirements for a detached accessory dwelling unit in Portland?

Requirements for a detached accessory dwelling unit in Portland include adherence to zoning laws regarding setbacks, lot coverage, and height restrictions. The structure must also meet all building codes for safety and habitability. Local professionals are well-versed in these specific regulations.

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What is involved in ADU construction in Portland?

ADU construction in Portland begins with design and obtaining permits. This is followed by site preparation, foundation work, and framing. Utility connections, insulation, and exterior finishing come next. The interior is then completed, followed by final inspections. Experienced crews manage each phase.

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, Hawthorne District, Alberta Arts District, Sellwood-Moreland, Laurelhurst — and every surrounding area.