Doyle Construction

300 Deschutes Way Southwest, Tumwater, WA 98501 49.5 miles

Harmony Architecture Studio

1324 Lombard Avenue, Everett, WA 98201 25.6 miles

Puget Sound ADU Builders

4712 South Morgan Street, Seattle, WA 98118 5.8 miles

Licensed 25 years in business Eco-Friendly

Puget Sound ADU Builders is a leader in ADU construction in western Washington state, excelling in design, construction, finishing, and permitting ADUs, DADUs, backyard cabins, garage conversions, duplexes, town homes, and multi-unit projects.

Cast Architecture

115 North 36th Street, Seattle, WA 98103 2.7 miles

15 years in business In-House Architect 80 ADU projects completed

Cast Architecture specializes in ADU and backyard cottage design in Seattle since 2009. With 80+ projects, their Cedar Cottage is pre-approved by Seattle & Kirkland. Award-winning designs include Widner Cottage and Lichtenstein Studio. Visit c... read more

Heartwood Builders

1902 North 34th Street, Seattle, WA 98103 1.9 miles

Eco-Friendly

Heartwood Builders is a Seattle ADU contractor specializing in backyard cottages, basement ADUs, and mother-in-law suites. They handle permitting, use sustainable materials, and help homeowners add rental income or family housing.

SkyDADU

Kent, WA 98042 19.8 miles

Luxury Builds

SkyDADU is a DADU builder and equity partner serving King, Snohomish, and Pierce counties in Washington State. They offer fixed-price packages, up to 100% funding, and handle permitting, construction, and condominiumization for detached accessory ... read more

Microhouse

114 North 42nd Street, Seattle, WA 98103 2.9 miles

Microhouse is a Seattle-based ADU builder specializing in custom detached ADUs (DADUs). They guide homeowners through zoning, design, and construction. Seattle permitted 551 DADUs in 2022, with a 40% increase in 2023. Microhouse offers site assess... read more

Cornerstone Builders LLC

261641 U.S. 101, Sequim, WA 98382 48 miles

Licensed 40 years in business

Cornerstone Builders LLC is a Sequim-based ADU builder serving Washington's North Olympic Peninsula for 40+ years. This certified design-build firm manages all phases—design, permitting, and construction—offering transparent, process-driven AD... read more

Lakeside ADU & Home Planning

1901 Vernon Road, Lake Stevens, WA 98258 29.8 miles

Lakeside ADU & Home Planning, based in Lake Stevens, WA, is a full-service ADU builder serving the Puget Sound Region. They specialize in backyard cottages, mother-in-law suites, garage conversions, and new builds, managing design, permitting,... read more

Armada Design & Build Inc.

15600 Northeast 8th Street, Bellevue, WA 98008 9 miles

Licensed 14 years in business Luxury Builds

Armada Design & Build Inc., Bellevue, WA, offers full-service residential design-build since 2011. Specializing in remodels, home additions, and custom builds across Puget Sound, they deliver turnkey solutions with in-house design and quality ... read more

Red's Construction & Renovation

Federal Way, WA 98003 21.2 miles

Licensed

Red's Construction & Renovation serves Federal Way & South King County, WA, specializing in ADU construction including detached, attached, garage conversions & basement units. Costs range from $50K–$300K+. Licensed, insured, transpar... read more

Era Builders

911 Northeast 70th Street, Seattle, WA 98115 4 miles

Eco-Friendly

Era Builders is a Seattle-based ADU contractor offering detached ADU construction, design, permitting, remodeling, and commercial renovations. They handle full ADU projects compliant with Seattle zoning rules, using sustainable practices.

Twin Brothers Group

14205 Southeast 36th Street, Bellevue, WA 98006 8.7 miles

Licensed

Twin Brothers Group is a licensed framing contractor in Washington State specializing in ADU, DADU, garage conversions, and home additions across King and Snohomish County, serving Seattle-area GCs and owner-builders.

Avio Homes

10908 62nd Street East, Puyallup, WA 98372 29 miles

Avio Homes is a Seattle-based ADU contractor specializing in detached ADUs, backyard cottages, and in-law suites. Serving Seattle, Tacoma, and Olympia, they handle design, permitting, and construction with local zoning expertise.

Levite Construction CO

5608 17th Avenue Northwest, Seattle, WA 98107 4.2 miles

Licensed Eco-Friendly

Levite Construction Co is a Seattle-based family-owned general contractor offering kitchen remodeling, bathroom remodeling, ADU construction, garage conversions, new builds, interior design, and more across the Greater Seattle area.

Other cities in Washington

What you need to know

Seattle's Progressive ADU Policies Make It a Leader in Accessory Dwelling Units

Seattle, Washington has become one of the most ADU-friendly cities in the United States. In 2019, the city passed landmark legislation that significantly relaxed restrictions on Accessory Dwelling Units (ADUs), allowing homeowners to build both an attached ADU and a detached ADU (DADU) on the same property simultaneously. This progressive policy shift has created a booming demand for experienced ADU contractors in Seattle, making it essential to find professionals who understand the city's unique regulatory landscape.

Key Seattle ADU Regulations Your Contractor Must Know

Hiring a knowledgeable Seattle ADU contractor means working with someone who is well-versed in the city's specific building codes and zoning requirements. Seattle's Department of Construction and Inspections (SDCI) oversees all ADU permits, and navigating this process requires expertise. Some critical regulations include:

What to Look for in a Seattle ADU Contractor

Finding the right ADU builder in Seattle is critical to the success of your project. The city's hilly terrain, frequent rainfall, and older housing stock present unique construction challenges. A qualified contractor should have experience working with Seattle's soil conditions, understanding of stormwater management requirements, and familiarity with the city's energy code, which aligns with Washington State's strict energy efficiency standards. Always verify that your contractor holds a valid Washington State contractor's license and carries proper liability insurance.

The ADU Permitting Process in Seattle

The permitting process for ADUs in Seattle can be complex and time-consuming. Working with an experienced Seattle ADU contractor who understands the SDCI's online permitting portal and plan review process can save significant time and money. The typical steps include:

Why Investing in an ADU in Seattle Makes Financial Sense

With Seattle's consistently high rental demand and competitive housing market, building an ADU is a smart financial investment. Seattle ADU contractors report strong interest from homeowners looking to generate rental income, house family members, or increase overall property value. Whether you're considering a backyard cottage, a garage conversion, or a basement ADU, partnering with a skilled and licensed contractor who knows Seattle's building environment is the key to a successful and compliant project.

ADU Contractors near Seattle, WA