
Dumas Build LLC
Dumas Build LLC. Construction company. 523 NE 81st St, Seattle, WA 98115
Looking for the best in-law suite builders in Seattle, Washington? Our directory features 118 vetted in-law suite builders serving the Seattle area. Whether you're planning a new ADU construction, garage conversion, or backyard cottage, find the right builder for your project.

Dumas Build LLC. Construction company. 523 NE 81st St, Seattle, WA 98115

Fuller Living Construction. General contractor. 5304 Green Lake Way N, Seattle, WA 98103, United States

Seattle Upgrade Construction LLC. Handyman/Handywoman/Handyperson. 13725 32nd Ave NE, Seattle, WA 98125

BUILD LLC. Contractor. 5512 1st Ave NE, Seattle, WA 98105, United States

Seattle Modern Buildings ADU Builder is a Seattle-based design-build firm specializing in detached ADUs, duplexes, and modern homes.

Metis Construction. General contractor. 941 S Nebraska St, Seattle, WA 98108, United States

AM Contracting LLC. Construction company. 108 S 108th St, Seattle, WA 98168, United States

Exceptional Home Builders. Remodeler. 1525 11th Ave, Seattle, WA 98122, United States

Toepfer Construction Co. General contractor. 6528 Phinney Ave N, Seattle, WA 98103, United States

AAA Builders LLC. Handyman/Handywoman/Handyperson. 2100 N 106th St, Seattle, WA 98133, United States

Seattle Backyard Homes. Home builder. 4813 37th Ave NE, Seattle, WA 98105, United States

Cascadia ADU. Custom home builder. 901 1st St, Snohomish, WA 98290

Seattle-ADU. General contractor. 509 Olive Wy, Seattle, WA 98101, United States

microhouse. Architect. 114 N 42nd St, Seattle, WA 98103, United States

Seattle ADU Solutions. Construction company. Closed · Opens 8 AM Mon

Full Service, Licensed Kitchen & Bath Remodelers in Seattle

1AD Studio LLC. Architectural designer. Closed · Opens 8 AM Mon

abode builds. Contractor. 2880 NW Market St, Seattle, WA 98107, United States

Build-Up Construction. Remodeler. 701 5th Ave S Suite 4200, Office number 4266, Seattle, WA 98104, United States

Proform Builds. Custom home builder. 701 NE Northlake Way, Seattle, WA 98105, United States
Seattle is one of the top markets for accessory dwelling units in Washington. With growing demand for affordable housing, ADU construction in Seattle offers homeowners an excellent opportunity to add living space, generate rental income, or house family members. Our curated list of in-law suite builders in Seattle helps you find experienced professionals who understand local building codes, zoning regulations, and permit requirements.
ADU construction costs in Seattle typically range from $150,000 to $350,000 depending on size, design, and finishes. Garage conversions are generally less expensive ($80,000–$150,000), while custom-built detached ADUs can cost more. Get free quotes from our listed in-law suite builders to compare prices.
Yes, ADU construction in Seattle requires building permits. Washington has specific ADU regulations, and local zoning laws may have additional requirements. Our listed builders can help you navigate the permitting process.
ADU construction timelines in Seattle typically range from 4–12 months, depending on the project type. Prefab ADUs can be installed in 2–4 months, while custom builds may take 8–12 months including design and permitting.