Attached ADU near Mercer Island, WA

At Puget Sound ADU Builders, we create functional and cozy and ADUs (Accessory Dwelling Units) in Washington. Our company was founded by Tanya Mills and built on a passion for providing high-quality, affordable housing solutions that unite families. With rising costs in traditional housing and care, we offer practical alternatives that allow your loved ones to live independently in comfortable spaces—right in your backyard.

Gravity Builders LLC is a licensed ADU contractor and custom home builder in Renton, WA. Specializing in ADU/DADU construction, custom homes, outdoor living spaces, and concrete work, they deliver quality craftsmanship with transparency and integrity.

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.

Bicknell Builds offers ADU construction in the greater Seattle area, including detached ADUs, backyard cottages, granny flats, and in-law suites. Ideal for rental income, family housing, or added property value.

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.

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, transparent pricing.

Huskies Construction in Renton specializes in home additions, ADUs, and DADUs. Services include garage conversions, granny flats, in-law suites, backyard cottages, and room additions, helping homeowners expand living space or generate rental income.

Greater Seattle Remodeling builds code-compliant ADUs across the Seattle metro, including detached ADUs, garage conversions, and basement apartments. They match homeowners with vetted contractors for permits, design, and construction.

Neil Kelly Washington offers ADU design and build services in the Northwest, including detached ADUs, garage conversions, and attached units. Their team navigates local permits, balances design with functionality, and helps homeowners add value through custom accessory dwelling units.

Seattle-based United Signature specializes in ADU & DADU construction. They offer custom design, permitting, and project management. Benefits include rental income, multi-generational living & versatile spaces. Financing available via Enhancify.

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 assessments and tailored DADU solutions.

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 living space.

An ADU (accessory dwelling unit) is a secondary dwelling on a single-family lot. Types include basement apartments, garage conversions & detached cottages. Costs vary by size, design, permits & materials. Professional ADU contractors ensure smooth project execution.