Detached ADU in Washington

Tenhulzen Construction offers ADU and DADU construction services in Washington State, providing pre-approved and custom plans. Options suit various budgets and timelines, with benefits including added property value and flexible living spaces.

Signature ADU is an experienced ADU builder offering full-service design and construction. Their team includes experts in architecture, general contracting, and project management, handling detached ADUs, garage conversions, granny flats, and in-law suites from start to finish.

Skagit Design Homes offers flexible ADU plans for detached units, backyard cottages & granny flats. Maximum ADU sizes vary by local zoning laws. Check municipal regulations early to ensure your accessory dwelling unit project stays on track.

New Image Construction Management is a Washington State general contractor and building company based in Seattle, WA. With a primary focus of new home construction and renovation of residential and commercial properties.

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 castcottages.com.

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.

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.

True Built Home builds custom ADUs in Washington & Oregon, offering 14 floor plans from 495–1,199 sq ft, priced from $119,900. Plans include granny flats, in-law suites & backyard cottages with transparent pricing and customizable designs.

MyADU is a licensed ADU contractor in Vancouver, WA, specializing in custom accessory dwelling units across the Pacific Northwest. Founded in 2019, they offer design, permitting, and turnkey builds, completing most projects in 6–9 months.

JDI Construction is a Portland-based ADU contractor offering full design-build services for detached, attached, garage conversion, basement, above-garage, and interior ADUs, including permits and eco-friendly practices.

Northwest ADU is a trusted ADU builder in Mill Creek, WA, offering full-service accessory dwelling unit construction, including detached ADUs, garage conversions, and basement conversions, with expert permit and zoning support.

Chapman Projects offers ADU design and construction in Seattle, Bellevue, and King County. With 20+ years of experience, they provide custom accessory dwelling units, detached ADUs, and backyard cottages using sustainable building practices.

Rybak & Company LLC builds ADUs in Vancouver, Camas, Washougal & Portland Metro. Services include detached ADUs, garage conversions & in-law suites. Projects start at $175K–$250K+. Free estimates available.

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.