Attached ADU near Mount Vernon, WA

Bellingham ADU Builders offers full-service ADU construction in Whatcom County, including detached and attached ADUs. Costs range from $200K–$550K+. Permits included. Free 48-hour feasibility study available. HB 1337 allows up to two ADUs per lot.

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, and construction.

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.

NorthLight Custom Builders offers ADU construction in King & Snohomish County. Services include attached & detached units for rental income, family living, or home offices. Structured process from consultation to one-year warranty follow-up.

Cruvers Contracting LLC builds ADUs in Snohomish, WA, tackling rural challenges like septic systems, slopes, and wooded lots. Serving areas including Lake Stevens, Monroe, and Everett with phased planning and durable, site-specific construction.

Evola Builds LLC, led by Michael and Amber Evola, offers residential renovation and construction services including bathroom remodels, ADU work, garage conversions, and structural modifications, collaborating closely with architects and homeowners.

Cascadia ADU builds attached, detached, garage & basement ADUs across King, Snohomish, Skagit & Chelan Counties, WA. Full-service design, permitting & construction completed in 8–10 weeks with 10+ years experience.

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.

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.

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.