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The Best Accessory Dwelling Unit Builders in Seattle, Washington

10 Min Read

Seattle, Washington, is a vibrant city that beckons with its unique charm. With its stunning natural surroundings, including the iconic Puget Sound and majestic mountains, it’s a haven for outdoor enthusiasts. The city has a diverse and welcoming community, making it a great place to call home.

The city combines the best urban living with nature’s tranquility, creating a unique experience that makes it an exceptional place to settle down and thrive.

To find the right ADU builder in Seattle, navigating the sea of options is essential. This curated list introduces you to eight exceptional ADU builders in Seattle, Washington, who have garnered recognition for their craftsmanship and dedication.

Whether you’re looking to add a cozy backyard cottage or an urban loft, these builders have the expertise to turn your vision into reality.

CRD Design Build

2707 NE. Blakeley St., Seattle, WA 98105

CRD Design Build, a Seattle-based design-build firm, has shaped the remodeling landscape since 1980 under the visionary leadership of owner Denny Conner. The firm’s essence lies in bridging the gap between homeowners’ dreams and budgets, pioneering the design-build approach in the early 1990s. CRD Design Build is a testament to treating customers with respect and dignity.

CRD’s collaborative spirit sets it apart, working closely with architectural designers to ensure clients’ dreams come to life within budget constraints. This personalized approach defines its work ethic, delivering remarkable results aligning with each client’s vision.

A standout project in CRD’s portfolio is the transformation of a Wallingford home’s backyard into a detached oasis. This endeavor showcases its ability to convert small spaces into functional, striking extensions of the house, blending indoor and outdoor living seamlessly.

For four decades, CRD Design Build has merged creativity, integrity, and client dreams to create exceptional living spaces.

Jackson Design Build, LLC

7543 15th Ave. NW., Seattle, WA 98117

Jackson Design Build LLC, established in the heart of Seattle in 1999 by Leif and Sarah Jackson, along with Leif’s brother, Erik, represents the embodiment of integrity and craftsmanship in the remodeling industry. With a collective half-century of experience, this family-founded firm is deeply committed to its craft. In 2019, the addition of partner Josh Zautke further enriched the team, with Josh’s invaluable contributions dating back to 2008.

The company has a sterling reputation for excellence, underpinned by a steadfast commitment to honesty, reliability, and exceptional service. Its impressive accolades include 14 REX awards for Remodeling Excellence and three Merit awards.

One notable project that exemplifies its prowess is the Phinney Ridge Backyard Cottage. In this endeavor, Jackson Design Build LLC showcased its structural assessment expertise and ability to craft inviting spaces. The result is a charming two-bedroom cottage, a cozy haven for guests, and a productive writing studio adorned with custom bookshelves and a whimsical library ladder.

With a history of excellence, a passion for its craft, and a commitment to service, Jackson Design Build LLC embodies the essence of remodeling with integrity and artistry.

Ventana Construction, LLC

5958 California Ave. SW., Seattle, WA 98136

Ventana Construction is a seasoned remodeling firm renowned for its expertise in whole-house remodels, home additions, backyard cottages, and bespoke homes. Since its establishment, it has been committed to transparency and client engagement.

The firm’s portfolio is a testament to its craftsmanship, showcasing diverse projects that reflect creativity and functionality. One notable project, a charming backyard cottage, challenges conventional notions by residing in the front yard. This versatile space has salvaged cabinets, cleverly tucked appliances, and a thoughtfully designed living area.

Ventana Construction has been honored with the prestigious Big 50 award by Remodeling Magazine in 2015. Its affiliations with esteemed organizations like the National Association of Home Builders (NAHB) and the Master Builders Association (MBA) underscore its commitment to quality and professionalism.

Ventana Construction embodies the essence of Seattle living in a city known for innovation and design, blending thoughtful craftsmanship with a passion for creating spaces that truly inspire.

Potter Construction, Inc.

5639 California Ave. SW., Seattle, WA 98136

Potter Construction, a long-standing presence in the greater Seattle area since 1979, is a testament to the enduring commitment to craftsmanship and design. The firm specializes in a comprehensive remodeling approach encompassing everything from initial design and permits to the final construction phase. 

Its key distinction lies in its ability to turn the complexities of home remodeling into a seamless journey. The team of experienced design/build professionals at Potter Construction ensures the client’s remodel is not just a construction project but a transformation of their living space. 

One notable project that showcases its expertise is the West Seattle Backyard Cottage. Converting a space intended for a car into a bright and airy living area required vision, and Potter Construction delivered. The result is a 600-square-foot cottage that feels remarkably spacious, with tall ceilings, natural light, and thoughtful design elements that maximize functionality.

With accolades like the 2021 Rex Awards Winner and affiliations with esteemed organizations such as the National Association of Home Builders (NAHB) and the National Kitchen and Bath Association (NKBA), Potter Construction embodies a commitment to excellence that defines its legacy.

Built Square, LLC

4601 Shilshole Ave. NW., #5, Seattle, WA 98107

Built Square is a residential remodeling company renowned for its commitment to excellence. With an unwavering dedication to craftsmanship and sustainability, it is a beacon of quality in the remodeling industry.

At Built Square, it’s not just about bricks and mortar; it’s about creating thoughtfully designed spaces that breathe life into the client’s vision. The company uses top-tier, eco-friendly materials and techniques to transform houses into homes. Its hallmark is transparent communication, ensuring dreams and needs are met at every step of the remodeling journey.

One significant project that reflects Built Square’s prowess is the Montlake DADU. This intricate detached accessory dwelling unit seamlessly integrates with the original house, showcasing its technical prowess. From matching century-old flagstones to navigating challenging terrain, Built Square’s expertise shines through.

With affiliations in prestigious industry associations like the National Kitchen and Bath Association (NKBA) and the Master Builders Association (MBA), Built Square is a trusted name in the field. The company was founded by Divven Browne and Nathan Werner, both University of Washington alums, and embodies a fusion of expertise and innovation.

Mighty House Construction

3108 SW. Webster St., Seattle, WA 98126

Mighty House Construction, founded by a passionate third-generation construction specialist and a green building enthusiast, embodies two decades of commitment to excellence in Greater Seattle and the East Side areas. The full-service general contracting company brings a unique blend of skill, responsiveness, and reliability to every project, whether a simple renovation or an expansive whole-house remodel.

Mighty House Construction values outstanding craftsmanship and delivers exceptional value to its clients. It excels in turning homeowners’ visions into reality, consistently exceeding expectations with its expertise in residential remodeling and building services.

One noteworthy project that exemplifies the firm’s commitment is the Built Green Ravenna DADU (Detached Auxiliary Dwelling Unit). This project expanded living space and incorporated super energy-efficient building solutions and health-conscious finishes, earning a Built Green 4-Star Certification. 

With affiliations like the National Association of Home Builders (NAHB) and the Master Builders Association (MBA) of King and Snohomish Counties, Mighty House Construction is deeply rooted in the industry, ensuring every project benefits from its vast experience and dedication to quality.

Fradkin Fine Construction, Inc.

605 1st Ave., Suite 400, Seattle, WA 98104

Fradkin Fine Construction, Inc. has been clients’ trusted partner in turning their dreams into reality for three decades. With a profound understanding of clients’ emotional and financial investments in their homes and custom projects, it stands out for its commitment to an open, enjoyable construction process.

Its unwavering dedication to creating visually appealing, durable, and sustainable projects sets it apart. From that initial napkin sketch to the completion, Fradkin Fine Construction works hand in hand with clients, their architects, and designers. The team ensures clients’ visions for the perfect home become a dream and a feasible, sustainable, and budget-friendly reality.

It blends sustainable construction practices with top-notch materials, fostering a positive, collaborative relationship with clients and design professionals. By combining craftsmanship and creativity, the team delivers remarkable projects.

One notable example is its contemporary detached accessory dwelling unit in Seattle’s Greenlake neighborhood. This compact yet light-filled design showcases its commitment to energy efficiency and creativity. 

Toepfer Construction Company, LLC

6528 Phinney Ave. N., Seattle, WA 98103

Founded in 1989, Toepfer Construction is a family-owned business deeply rooted in the Seattle area, specializing in residential renovations, additions, and custom homes. Its unwavering commitment sets it apart to turn clients’ visions into reality while ensuring a seamless, on-time, and budget-friendly building process.

With a legacy spanning three generations of builders, Toepfer Construction brings expertise to every project. The team at Toepfer Construction works hard to craft dreams and build lasting constructing spaces.

One significant achievement is the Sunset Hill DADU project, which exemplifies its dedication to excellence. Recognized with the prestigious Home of Distinction award by the American Institute of Architects (AIA) in 2018, it showcases its ability to blend original design with quality craftsmanship. Publications like Seattle Magazine have also featured its work, further attesting to its impact on the local architectural and construction landscape. 

Sunset Hill Garage/Loft. Image license: SHKS Architects and Toepfer Construction Company LLC. © Copyright 2017 Benjamin Benschneider All Rights Reserved. Usage may be arranged by contacting Benjamin Benschneider Photography. Email: or phone: 206-789-5973.

For 30 years, Toepfer Construction has transformed spaces, enhanced lives, and made dreams come true, all while honoring a rich family tradition of building excellence.


  • Brooke Adams

    Brooke is a Deputy Editor at Seattle Architects with around five years of professional experience as a writer and editor in the construction and home improvement space. Her expertise covers a wide range of topics including addition construction, home remodeling, and landscape design. Brooke has a Bachelor's degree in Civil Engineering, and she also brings extensive experience as a project manager for a top construction firm, overseeing multi-million dollar projects. Additionally, she is certified in LEED and OSHA safety standards. Expertise: Addition Construction, Home Remodeling, Landscape Design Key Highlights: Over 5 years of experience writing and editing in the construction space, Deputy Editor at Seattle Architects Education: Syracuse University, Bachelor of Science in Civil Engineering, Certificates in Public Relations and Social Media

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