Seattle ADU & DADU Construction: Maximize Your Property's Value

All Fixtures, materials, and labor included

Built by a local, vetted contractor

3 Weeks Average Time To Complete

Incorporating Festive Patterns

Textures Into Your Holiday Home Decor

Smart Space That Works Harder For You

Your property has hidden potential. That unused yard space or that basement collecting dust could become a valuable living area that generates $2,000+ monthly through rental income or gives family members their own space with privacy intact.

Seattle’s updated ADU rules have opened new doors for homeowners. As experienced Seattle ADU builders located in Everett, WA, we’ve helped dozens of property owners navigate regulations, design functional spaces, and build quality structures that stand the test of time. Our backyard cottages and basement apartments blend seamlessly with existing homes while maximizing every square foot of allowable space.

Why Seattle Homeowners Choose Our ADU & DADU Building Services

Regulation Know-How: We stay current with Seattle's ADU/DADU rules so your project moves forward without surprises.
Space Maximizers: Our designs capture every usable square foot while meeting all code requirements.
Permit Specialists: Years of working with Seattle's building department means smoother approvals and fewer delays.
Smart Investments: We design with rental appeal in mind, creating spaces that attract quality tenants and strong returns.

ADU & DADU Projects Throughout Seattle's Neighborhoods

We’ve built accessory dwelling units across the Greater Seattle Area – from Ballard’s tight lots to West Seattle’s slopes, from Wallingford’s alley-access properties to Fremont’s historic districts. Each neighborhood brings different challenges, whether it’s managing difficult terrain, working with existing structures, or navigating specific overlay requirements.

Our experience building mother-in-law apartments and backyard cottages throughout the city means we know what works where. We select materials and design elements that perform well in Seattle’s climate while matching the architectural character of your neighborhood.

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Build, Convert, Expand: Expert Home Services Across the Greater Seattle Area

CUSTOM BUILD

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HOME ADDITIONS

Seamless Home Additions

CONVERSIONS

Complete Home Conversions

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Financing That Makes Sense

Many Seattle homeowners are surprised to discover their ADU project can pay for itself faster than expected. We partner with lenders who understand the income potential of accessory dwelling units and offer specialized financing packages that account for future rental revenue.

With Seattle’s strong rental market, many clients find their ADU generates enough monthly income to cover loan payments while building equity. We’ll help you run the numbers for your specific property to see how the investment pencils out over time.

Frequently Asked Questions About Seattle ADU & DADU Construction

How much does it cost to build a DADU or ADU in the Greater Seattle Area?

Building an ADU or DADU in Seattle typically ranges from $150,000 to $400,000, depending on unit size, location, finishes, and specific site conditions. Basement ADUs generally start around $150,000, while detached structures average $300-$400 per square foot due to foundation and utility requirements.

How long does it take to build an ADU or DADU?

Construction typically takes about 4–8 months, including permitting, depending on your unit’s size, complexity, and site preparations. The permitting process usually accounts for 2-3 months of this timeline, with actual construction ranging from 3-6 months based on seasonal conditions and project scope.

What are Seattle's regulations for ADU and DADU construction?

The Greater Seattle Area has specific guidelines regarding unit size, setbacks, height restrictions, and occupancy rules. Current regulations allow up to 1,000 square feet for DADUs, no minimum lot size requirement, and the ability to build both an ADU and DADU on a single property. We manage the entire permitting process, ensuring compliance with all local regulations.

Can I rent out my ADU or DADU?

Yes, ADUs and DADUs are excellent rental opportunities, providing homeowners with additional income or comfortable accommodations for extended family and guests. Seattle’s strong rental market makes these units particularly valuable investments, with potential returns helping to offset construction costs over time.

What types of ADUs and DADUs can I build on my Seattle property?

We build a variety of unit types, including detached cottages, garage conversions, basement ADUs, above-garage apartments, studios, and multi-bedroom units, all designed to complement your existing home and property. Each style has specific advantages depending on your lot configuration, budget, and intended use.