Reliable ADU Builders in Portland, OR
ADUs pay off whether you wish to bring in some extra income, get a quiet home office, or build an art studio for your creativity to flourish.
For over three decades, COOPER Design Build has been reimagining spaces and crafting quality construction here in the Pacific Northwest. Building thoughtful, quality, free-standing accessory dwelling units is one of the areas we specialize in. Our integrated approach means our ADU designers and builders work hand-in-hand, so you get a smooth and cohesive process. Having Portland’s top accessory dwelling unit contractors by your side is the best way to get a high-quality result that feels just right for your property and your lifestyle.
Expertly managing your project
Your trusted ADU contractors with a fast-track building process
As leading ADU contractors, we have decades of experience, a collaborative approach, and a proven methodology that keeps your goals front and center. Our process is organized, transparent, and designed to avoid delays at every stage. From permitting to final walkthrough, we handle the details so you can stay focused on the big picture.
What makes us the go-to accessory dwelling unit builders in Portland
Experience you can trust
Over 30 years of design-build success means your project is in expert hands from start to finish.
Personalized attention
A small, passionate team of ADU contractors focused entirely on your needs and satisfaction. We’ll listen closely, communicate clearly, and work alongside you to breathe life into a space that truly reflects you.
Streamlined process
In-house collaboration between design and construction keeps every detail on track. We have a proven methodology that keeps your goals front and center.
Proven reliability
A flawless record with the BBB and state boards ensures total peace of mind and offers complete confidence.
Local expertise that makes a difference
We know Portland’s ADU rules and permitting process inside and out, so we can help you avoid delays and keep things moving smoothly from the start.
The right ADU builder changes everything
Building a detached ADU is a complex task, but you can rest easy as we’ll manage all stages of your project, from early planning to the final walkthrough. Our team handles site evaluation, permitting, and zoning, making the whole experience smooth and easy for you. With decades of providing exceptional home additions services, we know how to avoid common delays and keep the project moving forward.
Our designers and ADU builders work as one team, which means better communication, fewer surprises, and a design that fits your lifestyle. It’s how we deliver thoughtful, beautifully crafted spaces you’ll genuinely love. We take pride not just in the finished product, but in making the entire experience organized, transparent, and stress-free. From start to finish, your goals and peace of mind are always our top priority.
Live bigger without moving an inch
Frequently Asked Questions
How much does an ADU cost in Oregon?
The cost of a freestanding ADU in Oregon can vary widely based on size, design, site conditions, and finishes. Our builders work with you early in the planning process to align your goals with a realistic budget.
Whether your project is part of a larger outdoor living transformation or a stand-alone undertaking, we ensure everything is thoughtfully integrated into your property. This helps avoid unexpected costs by keeping everything transparent and coordinated from the start.
You will never be left guessing where your money is going. You get a complete, high-quality build with no surprises and a final result that reflects your vision, just like we’ve done for many home remodeling clients in Beaverton and other nearby areas.
What are the requirements for an ADU in Oregon?
There are state-wide ADU regulations in Oregon, and local jurisdictions like Portland or Lake Oswego often add their own requirements around size, height, parking, and more. Every contractor in Portland needs to keep up with every change in the code. We stay up-to-date with these changes and manage all zoning and permitting for you.
We’ll evaluate your property to ensure your project meets both state and local rules, and advise you on what’s possible before we begin designing it. You won’t need to navigate the red tape because we do it for you.
How close to my house can I build an ADU?
In Portland, the placement of a detached accessory dwelling unit relative to your primary residence and property lines is governed by specific zoning regulations. While there isn’t a mandated minimum distance between the new construction and the main house, it needs to adhere to the setback requirements of your property’s base zoning district. These setbacks typically include:
- Side and rear setbacks: Generally, a minimum of 5 feet from the side and rear property lines.
- Front setback: The unit must be located at least 40 feet from the front lot line or behind the rear wall of the primary dwelling.
It’s important to note that these requirements can vary based on the specific zoning of your property and any applicable overlay zones. However, this is nothing to worry about since your ADU contractors will handle all aspects of zoning analysis and site planning for you, just like for any home remodeling project.
What is the maximum size for an ADU?
Your ADU contractor will likely explain that in most Oregon cities, a detached accessory dwelling unit can be up to 800 square feet, though some areas allow more depending on your lot size and local code. The city recently lifted certain restrictions, which can open up larger build options if your site qualifies.
Your dedicated builder will take these variables into account when designing your space and will walk you through what’s allowed on your property. Our goal is to get you the most usable space possible while staying compliant. You’ll get a custom addition that maximizes both square footage and long-term value.
Who are the best accessory dwelling unit builders near me in Portland, OR?
COOPER Design Build is Portland’s trusted contractor, providing quality, custom home renovations, which include beautifully constructed freestanding ADUs. With decades of experience and a fully integrated team of designers and builders, we handle everything from design and permitting to construction and finishing details. We’re available for a range of projects across the area, including high-end home remodeling in Lake Oswego and much more.
Whether you’re tucked near Forest Park or overlooking the Willamette River, we bring thoughtful design and lasting value to every square foot. Schedule your consultation today and take the first step toward building something exceptional!
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