ADU Resources

Does building an ADU make sense for you?

Feasability

The first step is understanding what’s possible on your property. Factors like lot size, zoning designation, setback requirements, existing structures, and utility access all determine whether an ADU is feasible, and what type and size would work best. Every lot is different, and a professional assessment early on can save significant time and money down the road. We can help you navigate these variables or point you to the City of Seattle’s interactive feasibility tools to get started on your own.

Permitting

Building an ADU requires permits from your local jurisdiction, and the process can vary significantly depending on where you live. In Seattle, recent code changes have made ADU construction more accessible, but you’ll still need to navigate building permits, site plans, engineering reviews, and potentially environmental or utility approvals. The permitting timeline depends on the complexity of your project and how busy the jurisdiction is. Having experienced support through this process helps avoid costly delays and rejected applications.

Cost

ADU construction costs depend on size, complexity, site conditions, and finish level. A detached backyard cottage in the Seattle area can range from roughly $300,000 to $800,000 or more, depending on the scope. Costs include design, permitting, site preparation, utilities, construction through completion. Getting a realistic budget early; through a Rough Order of Magnitude estimate and pre-construction planning; helps you make informed design decisions before committing to construction.

Financing

There are several ways to finance an ADU project, including home equity loans, home equity lines of credit (HELOCs), construction loans, and cash-out refinancing. Some homeowners also explore local and state incentive programs designed to encourage ADU construction. The right option depends on your financial situation, timeline, and how you plan to use the unit. We recommend consulting with a lender experienced in ADU financing early in the process.

Return on Investment

An ADU can generate meaningful return on investment through rental income, increased property value, or both. Many homeowners in the Seattle area see rental income that significantly offsets their construction costs over time. Beyond the financial return, ADUs also offer flexibility; housing for aging parents, adult children, or guests; and contribute to the growing demand for housing in our region. The long-term value depends on location, unit quality, and how the space is used.

Additional Resources

The city of Seattle has created a website that is full of useful information. Even if your project is outside of Seattle, it’s a great place to start.

Visit ADUniverse

Step by Step Guide

Interactive Feasibility Map

ADU Rules: Seattle | Washington State

Pre-Approved DADU designs

Cameron McKinnon

“Through his hands-on experience in the field, Alex brings real world knowledge of how projects are actually built. This allows him to approach budgeting, contracting, scheduling, and scope clarification with a depth of understanding that is hard to replicate. His ability to bridge the gab between the field and the office makes him an incredibly effective and respected project manager.”

Emily Nelson

"What truly sets Alex apart is his extensive hands-on field experience. Unlike many project managers who work primarily from an office, Alex has actually built what he manages. This practical knowledge allows him to anticipate challenges, develop creative solutions, and communicate effectively with constructions crews."

Scott Atkins

"Over my three decades in this industry, it’s rare to come across a partnership like Alex and Ian’s. Both bring a strong combination of project management expertise and hands-on construction knowledge, which gives them a well-rounded, practical approach from planning through execution.

Alex stands out as the most detail-oriented and organized PM I’ve encountered, while Ian is an exceptionally talented carpenter whose craftsmanship speaks for itself. Just as important, they operate with a level of integrity that’s hard to find. They communicate clearly, follow through, and do exactly what they promise. That balance of shared capability and individual strengths makes them an easy recommendation for any project."

Kalem A

"Ian built the cabinets in my kitchen and they came out beautifully. From concept to installation, there was excellent communication throughout. The craftsmanship is the kind you can only get from someone who's been doing this a long time. He took the time to match the wood grain and made sure everything was done the way he'd do it in his own home. My wife couldn't be happier with the outcome, and that's what truly matters."

Ready to start planning?

Whether you have a clear vision or just the beginning of an idea, our pre-construction services will help you understand what’s possible—and what it will cost—before you commit to building. Reach out to start the conversation.