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.
read more
Better Builders is a Seattle-based general contractor specializing in residential remodeling, garage conversions, ADUs, kitchen and bathroom remodels, basement finishing, deck repairs, and exterior work, with dedicated project management.
read more
Explore pre-designed ADU floor plans from Modern ADU Plans — studio, 1-bed, 2-bed, garage conversions & more. Save time, reduce costs & maximize property value with ready-to-build accessory dwelling unit designs.
read more
LYD Construction is a Seattle-area ADU builder & remodeling contractor with 25 years of experience. Services include kitchen, bathroom, basement renovations, deck building & ADU construction. Financing up to $200,000 available. Based in Be... read more
Harjo Construction builds AADUs & DADUs in Seattle with 300+ projects since 2010. Costs range $275K–$650K, max 1,000 sq ft, 4–6 month build time. Seattle removed owner-occupancy rules, boosting ADU rental potential.
read more
Lindal Homes offers custom ADU and DADU kit home solutions across the US and Canada. Flexible floor plans, the Lindal Elements collection, and system-built construction make adding a backyard cottage or guest suite efficient and cost-effective.read more
Drew Thatcher Construction builds ADUs in Lakewood, WA, including detached units, attached ADUs, and garage conversions. Founded by a Navy nuclear engineer, they offer design-build services with local Pierce County expertise.
read more
Olympic View Building is an ADU contractor offering detached ADU construction, garage conversions, in-law suites, granny flats, and JADU services. They help homeowners add value and living space while navigating zoning laws and building codes.
read more
New Day Construction is a licensed ADU builder in Bellevue, WA, with 21+ years of experience and 250+ projects. They build detached, attached, garage, basement, and custom ADUs, managing permits and design from start to finish.
read more
Haas Development & Construction offers ADU & DADU construction in Greater Seattle. They handle planning, permits, design, and builds for attached & detached units, including prefab DADU plans, helping homeowners add rental income or fa... read more
Wise Choice Construction offers expert home additions & ADU builds in Seattle, WA. From detached ADUs and granny flats to in-law suites, they handle permits, zoning, and seamless integration—boosting property value and livable space.
read more
Northwest ADU is a full-service ADU contractor in Western Washington specializing in detached ADUs, garage conversions, and basement conversions. Serving Pierce, King, and Snohomish Counties, projects range from $180K–$350K+, taking 6–10 month... read more
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
Mallard Brothers Construction builds ADUs & Tiny Homes in Olympia, WA. They offer attached, detached, garage conversions & ADA-accessible units, managing design, permits & construction for property owners seeking rental income or extra... read more
Carriage Houses NW is a Pacific Northwest ADU builder specializing in infill housing. They develop ADUs, duplexes, and townhomes, partner with homeowners, and offer fee-to-build services, leveraging WA State HB 1110 and HB 1337 legislation.
read moreSeattle, 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.
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:
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 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:
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.