Attached ADU near Monroe, WA

Raincap Construction, a Seattle-based family-owned contractor, specializes in ADU and DADU construction. They build backyard cottages, in-law suites, and garage conversions, helping homeowners add living space, rental income, and property value.read more

Seattle Modern Buildings ADU Builder is a Seattle-based design-build firm specializing in detached ADUs, duplexes, and modern homes. With deep knowledge of Seattle permitting, zoning, and construction best practices, we help homeowners unlock thei... read more

Seattle ADUs offer rental income & flexible living. Coates Design Architects guides homeowners through detached, attached, garage & basement conversions. Costs range $200K–$350K+, with 7–11 month timelines. Sustainable design & per... 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

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., 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

Sockeye Homes designs & builds custom ADUs and DADUs, offering full-service support from permits to construction. Fixed-cost packages range from $218K–$335K+, suiting retirees, families & rental income seekers.

Emerald ADU Builders Seattle specializes in ADU design, permitting, and construction. They build detached ADUs, attached ADUs, and garage conversions, serving Seattle homeowners with quality craftsmanship and transparent pricing.

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 th... read more

Greenpod Design builds custom DADUs in Washington using SIP construction and sustainable materials. They handle permits, ADA-compliant design, and energy-efficient builds. WA law allows up to two ADUs per lot, up to 1,000 sq ft.

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.

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.

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.

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.