OMARC Design's single story tiny home is 24x8 ft with 182 sq ft of living space. Features include a lofted bed, full bathtub, electric kitchen, and 25-40% recycled materials. Ideal as an ADU, backyard cottage, or granny flat.
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An Accessory Dwelling Unit (ADU) is an independent living space on a single-family property. Washington State's HB 1337 boosted ADU construction, easing zoning rules, removing owner-occupancy requirements, and capping impact fees at 50%.
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Magnitude Construction offers custom home building, remodeling, and ADU construction in Kennewick, WA, serving the Tri-Cities area. Services include kitchen, bathroom, and whole home remodels, with local zoning expertise and transparent project ma... 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
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
Fortitude Construction Group is a Spokane-based design-build contractor specializing in custom ADUs, home additions, and new builds. Led by experienced professionals, they serve Spokane and surrounding areas with integrity-driven craftsmanship.read more
Seattle ADU & DADU contractor Emerald City Construction & Renovation builds accessory dwelling units across Seattle, Bellevue & Eastside. Projects cost $350K–$500K+, take 8–14 months, and support rental income, multigenerational li... read more
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 Enha... read more
ADU Builders Seattle (Maksymov Brownstone LLC) specializes in detached ADU construction across Seattle & King County. Licensed & bonded, they handle zoning, permits, and SDCI approvals. Services include backyard cottages, two-story units, ... read more
Home Care Contractors builds ADUs in King County, including DADUs, garage conversions, and basement units. They handle permits, design, and construction. Costs range from $300K–$700K, with timelines of 7–13 months total.
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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-u... read more
Seattle's 2019 ADU law changes made it easier to build accessory dwelling units on single-family lots. DADUs can't exceed 50% of the main home's size. No parking required. New detached ADUs start around $350,000.
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West Coast Homes, a Lynden, WA tiny home builder, specializes in accessory dwelling units (ADUs) like backyard cottages and in-law suites. They offer IRC-compliant plans, custom designs, and permitting guidance for Pacific Northwest homeowners see... read more
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 ensur... read more
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.
read moreWashington State has become one of the most ADU-friendly states in the nation, largely due to landmark legislation passed in recent years. In 2023, Washington enacted House Bill 1337, which significantly expanded ADU rights across the state. This law requires cities and counties to allow at least two ADUs per single-family lot, prohibits owner-occupancy requirements, and eliminates many restrictive parking mandates. For homeowners and ADU contractors in Washington, this legislation opened up tremendous opportunities to add accessory dwelling units to residential properties throughout the state.
While HB 1337 sets a statewide baseline, experienced ADU contractors in Washington State must still navigate local building codes and permitting processes that vary by jurisdiction. Cities like Seattle, Bellevue, Tacoma, and Spokane each maintain their own specific requirements regarding setbacks, height limits, and design standards. For example, Seattle allows ADUs up to 1,000 square feet for detached units and has its own streamlined permitting process. A knowledgeable Washington ADU contractor will be well-versed in these local nuances to ensure your project moves forward without costly delays.
Professional ADU builders in Washington are experienced in constructing a wide variety of accessory dwelling unit types to suit different property layouts and homeowner needs. Common ADU types include:
Choosing the right ADU contractor in Washington is critical to the success of your project. Washington State requires all general contractors to be licensed through the Washington State Department of Labor & Industries (L&I). Always verify your contractor holds a valid L&I license and carries proper liability insurance and workers' compensation coverage. Look for contractors with demonstrated experience in ADU construction specifically, as these projects involve unique challenges including utility connections, zoning compliance, and energy code requirements under the Washington State Energy Code (WSEC).
Investing in an ADU with a qualified Washington contractor offers significant long-term advantages. Homeowners can generate rental income to offset mortgage costs, provide housing for aging family members, or increase overall property value. With Washington's high housing demand, particularly in the Puget Sound region, ADUs represent a smart and increasingly accessible investment. Working with an experienced, licensed ADU contractor in Washington State ensures your project is completed safely, legally, and to the highest standards.