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ADU Contractors near Mercer Island, WA
NW Finishing
2265 116th Avenue Northeast, Bellevue, WA 98004 4.9 milesNW Finishing is a Seattle-area ADU contractor offering full-service accessory dwelling unit design and construction. Serving Bellevue, Kirkland, Redmond, Renton, and more, they handle permits, planning, and builds for detached, cottage, and prefab... read more
Alta Group Seattle
500 Southeast Everett Mall Way, Everett, WA 98208 23.7 milesThe DADU Guy
2522 North Proctor Street, Tacoma, WA 98406 23.7 milesThe DADU Guy is a Tacoma-based detached ADU builder serving Pierce County, WA. Specializing in DADUs, garage conversions, and basement conversions, they offer 5 floor plans, guaranteed pricing, and full project management to maximize property valu... read more
Wise Choice Construction
11626 Southeast 168th Street, Bellevue, WA 98058 8.1 milesWise 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.
read moreCast Architecture
115 North 36th Street, Seattle, WA 98103 8.3 milesCast 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 c... read more
Seattle Remodeling LLC
17202 Aurora Avenue North, Shoreline, WA 98133 14 milesSeattle Remodeling LLC specializes in ADU construction in Seattle, offering mother-in-law suites, backyard cottages, garage conversions, and granny flats. They help homeowners add value, rental income, and flexible living space.
read moreTacoma DADU
7809 Pacific Avenue, Tacoma, WA 98408 24 milesTacoma DADU Builders is a premier detached ADU builder serving Tacoma and Puget Sound. With 40+ years of experience, they offer turnkey ADU construction—design, permitting, and build—for investors, homeowners, and first-time buyers.
read moreEvola Builds LLC
Poulsbo, WA 98370 22.5 milesEvola 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... read more
Era Builders
911 Northeast 70th Street, Seattle, WA 98115 8.8 milesEra 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.
read moreRenovate Builders
4555 39th Avenue Southwest, Seattle, WA 98116 7 milesGiant Builders Seattle
125 Boren Avenue South, Seattle, WA 98144 4.5 milesGiant Builders Seattle is a Kent, WA general contractor with 20+ years of experience offering ADU construction, garage conversions, kitchen & bathroom remodeling, room additions, roofing, deck building, and more.
read moreHome Care Contractors
10634 East Riverside Drive, Bothell, WA 98011 13.2 milesHome 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.
read moreAlfa Framing
7345 164th Avenue Northeast, Redmond, WA 98052 8.9 milesAlfa Framing offers residential construction services including structural framing, siding installation, roofing, and ADU/DADU construction. Serving new builds and additions, they bring decades of experience and a solution-oriented approach.
read moreADU Builders Seattle
4712 South Morgan Street, Seattle, WA 98118 2.4 milesADU 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
Other cities in Washington
- Bainbridge Island
- Battle Ground
- Bellevue
- Bellingham
- Black Diamond
- Bothell
- Bremerton
- Buckley
- Burbank
- Camas
- Edmonds
- Everett
- Fall City
- Federal Way
- Kennewick
What you need to know
Building ADUs on Mercer Island: Navigating a Unique Island Community
Mercer Island, Washington, is a distinctive residential community situated entirely on an island in Lake Washington, connected to Seattle and Bellevue via Interstate 90. This unique geography creates specific challenges and opportunities for ADU contractors in Mercer Island. The city is known for its affluent, tree-lined neighborhoods, strict environmental protections, and limited land availability — all factors that make accessory dwelling units (ADUs) an increasingly attractive solution for homeowners looking to maximize their property's potential.
Mercer Island ADU Regulations and Zoning Requirements
Before breaking ground, experienced Mercer Island ADU contractors must be well-versed in the city's specific zoning codes and building regulations. Mercer Island falls under King County jurisdiction for some matters but maintains its own municipal code. Key regulations homeowners and contractors need to understand include:
- ADU size limits: Detached ADUs (DADUs) are generally limited in square footage relative to the primary dwelling size.
- Setback requirements: Mercer Island enforces strict setback rules, particularly important given the island's many sloped and waterfront lots.
- Tree retention policies: The city has robust tree protection ordinances that ADU contractors must carefully navigate during site planning and construction.
- Critical areas regulations: Proximity to Lake Washington and various wetlands means many properties fall within critical area buffers, requiring additional environmental review.
- Owner-occupancy rules: Homeowners should verify current owner-occupancy requirements, which may affect rental ADU plans.
Types of ADUs Commonly Built in Mercer Island
Given the island's predominantly single-family residential character and lot configurations, ADU builders in Mercer Island, WA most frequently work on the following project types:
- Attached ADUs: Additions connected to the main home, ideal for lots with limited buildable area.
- Detached ADUs (DADUs): Separate backyard cottages or garage conversions, popular in larger Mercer Island lots.
- Interior ADUs (JADUs): Basement or ground-floor conversions within the existing home footprint, minimizing site disturbance.
Why Hire a Local ADU Contractor in Mercer Island?
Working with a licensed ADU contractor familiar with Mercer Island is essential for a smooth permitting and construction process. Local contractors understand the nuances of building on island terrain, including managing utility connections, dealing with the city's permit office, and respecting the community's high aesthetic standards. Mercer Island homeowners consistently prioritize quality craftsmanship and design that complements the area's natural beauty and upscale character.
Start Your Mercer Island ADU Project Today
Whether you're looking to create a rental income unit, house family members, or increase your property value, an ADU is a smart investment in Mercer Island's competitive real estate market. Connect with a qualified ADU contractor serving Mercer Island, Washington to discuss your project goals, review local code requirements, and begin the design and permitting process with confidence.