Basement ADUs
Basement ADUs are an excellent choice for Portland homeowners who want to get additional utility out of their basements and increase their living space and the value of their homes!
Portland ADU Design & Build | Serving Oregon & the Willamette Valley
Your Portland ADU Design & Build team – Where your dream ADU meets seamless execution and lasting impact.
Your Portland ADU Design & Build Journey Starts Here
Portland ADU Design & Build is your trusted team for helping homeowners turn underused space into lasting value. Whether you’re planning for rental income, multigenerational living, or long-term property value growth, an Accessory Dwelling Unit (ADU) can transform how your home works for you.
An ADU is a secondary residential unit built on the same property as your primary home. It may be:
- A detached backyard home
- A converted garage
- A finished basement or interior space
Done right, an ADU increases property value, creates housing flexibility, and can generate reliable supplemental income.
But building one isn’t simple.
Permitting, zoning, design constraints, budgeting, inspections – there are many moving parts. That’s where we come in – Your Portland ADU Design & Build Team.
“Innovative design that wows, construction that stands the test of time, and limitless opportunities for decades to come.”
Portland ADU Design & Build: Your One-Stop-Shop for Construction
We are a licensed and bonded Portland ADU Design & Build team serving the greater Portland area and Willamette Valley.
From initial concept to final key handover, we manage every detail of the process:
- Site analysis and feasibility
- ADU type selection
- Architectural and interior design
- Engineering and permitting
- Transparent cost evaluation
- Full construction and inspection
You won’t be coordinating multiple contractors or navigating regulations alone. We handle the complexities – while collaborating with you on the exciting parts.
As for the not-so-fun stuff? We roll up our sleeves and get it done – with complete transparency around costs, timelines, and expectations.
The result is a thoughtfully designed ADU that aligns with your goals and financial plan – built to stand the test of time.
Learn more about our ADU design build team or browse our completed Portland ADU projects.
A Streamlined ADU Design & Build Process
Building an ADU should feel exciting, not overwhelming. Our structured ADU design & build approach guides you step-by-step through:
Site Evaluation
We assess zoning, utilities, placement options, and feasibility.
Selecting the Right ADU Type
Detached, garage conversion, or basement – we help determine the best fit.
Preliminary Design
Interior and exterior concepts tailored to your property and vision.
Cost Review & Budget Planning
Clear pricing and realistic expectations.
Permit Application & Processing
We handle the regulatory process.
Construction & Final Inspection
Quality craftsmanship from foundation to finishes.
As a proud FIR contractor, we have the exclusive privilege of working with one inspector on qualifying projects – helping streamline permitting and accelerate timelines while maintaining high standards.
Premium construction means organization, clarity, and a process you can trust.
Built for Energy Efficiency & Long-Term Sustainability
We’re a licensed and bonded Portland ADU design & build team specializing in the greater Portland, Oregon and Willamette Valley areas.
We work with a diverse team of craftsmen to handle the A — Z of your ADU construction, so you can sit back, relax, and actually enjoy watching your dream ADU become your backyard (or in-home) reality.
As an elite FIR contractor, we have the exclusive privilege of working with ONE inspector — which means that for many of our projects, we get faster permits and inspections, and you get an expedited construction timeline, all while improving financial efficiencies!
We Use Collaborative Technology – So You’re Never in the Dark
Transparency isn’t a buzzword for us.
Our collaborative construction software gives you:
- Real-time schedules
- On-site progress photos
- Cost summaries
- Direct communication access
You can follow your project’s progress right from your phone.
We also provide 3D modeling during the design phase so you know exactly what to expect before construction begins.
Types of ADUs We Build
Every property is different. That’s why we design and build multiple types of ADUs based on your goals and site conditions.
144
Projects Completed
Detached
ADUs
Build a stand-alone backyard home for privacy and rental appeal.
Garage
ADUs
Transform underutilized garages into fully independent living spaces.
Basement
& Interior ADUs
Maximize existing square footage within your home.
Built for Energy Efficiency & Long-Term Sustainability
At an average of approximately 800 square feet, ADUs are naturally energy-efficient. Smaller footprints mean lower utility usage and reduced environmental impact.
We help you go further by advising on:
- Energy-efficient systems
- Sustainable building materials
- Smart design strategies that reduce long-term operating costs
Lower utility bills. Smaller carbon footprint. Long-term value.
Schedule a FREE ConsultationHear what some of our customers have to say:
You can’t go wrong with ADU Design & Build
“ADU Design & Build did a remarkable job in designing and building our ADU (which became a very successful AirBnB).
The quality of the design and craftsmanship was impeccable and has received many compliments from our guests.”
We are very happy with their work
“ADU Design & Build did a fantastic job on our garage conversion ADU.
They had great communication with quality craftsmanship, and all done on time.
We are very happy with their work and would definitely recommend them to anyone considering a contractor for their ADU.”
You should absolutely trust ADU Design & Build with your project
“I worked with this group for two projects. Both were done extremely well.
They provided us with a detailed bid that was very competitive and stayed on top of all of the details for us. They also provided regular updates and responded quickly if we ever had questions.”
Frequently Asked Questions About Building an ADU in Portland
What is an ADU?
An ADU (Accessory Dwelling Unit) is a secondary residential unit built on the same property as a primary home. It can be detached, attached, a garage conversion, or a finished basement space. It’s designed to function as a fully independent living area.
How much does it cost to build an ADU in Portland?
ADU costs vary depending on size, type, site conditions, and finishes. Detached ADUs typically require full construction, while garage and basement conversions may be more cost-conscious. During your consultation, we provide a realistic cost range based on your property.
How long does it take to build an ADU?
Timelines depend on design scope, permitting requirements, and construction complexity. Working with an experienced design-build team helps streamline the process and reduce delays.
Do I need permits to build an ADU in Portland?
Yes. ADUs must comply with Portland’s ADU zoning regulations and building codes. Our team manages permitting, engineering coordination, and inspections to ensure your project meets all requirements.
Which type of ADU is right for my property?
The best option depends on your lot size, existing structures, budget, and long-term goals. A site evaluation allows us to assess feasibility and recommend the most strategic approach.
Start Your Portland ADU Design & Build Journey Today!
If you’re feeling overwhelmed by the complexities of ADU design & build – or simply exploring what’s possible – you’re in the right place.
Let’s evaluate your property, clarify your options, and design something built for lasting impact.