ADU Contractors near Mercer Island, WA
Better Builders
5606 California Avenue Southwest, Seattle, WA 98136
7.3 miles
Better Builders is a Seattle-based general contractor specializing in residential remodeling, garage conversions, ADUs, kitchen and bathroom remodels, basement finishing, deck repairs, and exterior work, with dedicated project management.
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Levite Construction CO
5608 17th Avenue Northwest, Seattle, WA 98107
9.9 miles
Levite Construction Co is a Seattle-based family-owned general contractor offering kitchen remodeling, bathroom remodeling, ADU construction, garage conversions, new builds, interior design, and more across the Greater Seattle area.
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Mallard Brothers Construction
120 State Avenue Northeast, Olympia, WA 98501
47.7 miles
Mallard Brothers Construction builds ADUs & Tiny Homes in Olympia, WA. They offer attached, detached, garage conversions & ADA-accessible units, managing design, permits & construction for property owners seeking rental income or extra... read more
SkyDADU
Kent, WA 98042
14.5 miles
SkyDADU is a DADU builder and equity partner serving King, Snohomish, and Pierce counties in Washington State. They offer fixed-price packages, up to 100% funding, and handle permitting, construction, and condominiumization for detached accessory ... read more
Detray's Custom Housing
10209 149th Street East, Puyallup, WA 98374
30.9 miles
Bicknell Builds
19616 Southeast 310th Place, Kent, WA 98042
18 miles
Bicknell Builds offers ADU construction in the greater Seattle area, including detached ADUs, backyard cottages, granny flats, and in-law suites. Ideal for rental income, family housing, or added property value.
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BB Builders Pro
801 Southwest 16th Street, Renton, WA 98057
7 miles
BB Builders Pro specializes in ADU construction, garage conversions, home additions, and detached backyard cottages. Services include custom design, permitting, zoning compliance, and renovations—ideal for rental income or family housing.
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Harjo Construction
4900 15th Avenue Northwest, Seattle, WA 98107
9.5 miles
Harjo Construction builds AADUs & DADUs in Seattle with 300+ projects since 2010. Costs range $275K–$650K, max 1,000 sq ft, 4–6 month build time. Seattle removed owner-occupancy rules, boosting ADU rental potential.
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LYD Construction
4055 Lake Washington Boulevard Northeast, Kirkland, WA 98033
5.8 miles
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
Gravity Builders LLC
17422 108th Avenue Southeast, Renton, WA 98055
8.5 miles
Gravity Builders LLC is a licensed ADU contractor and custom home builder in Renton, WA. Specializing in ADU/DADU construction, custom homes, outdoor living spaces, and concrete work, they deliver quality craftsmanship with transparency and integr... read more
Zee Design & Build
570 Kirkland Way, Kirkland, WA 98033
7.8 miles
Zee Design & Build is a Kirkland, WA ADU contractor serving King, Snohomish, Skagit & Island Counties. Offering full-service ADU construction—garage conversions, basement units, backyard cottages & more—since 2012.
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Backyard ADU
4813 37th Avenue Northeast, Seattle, WA 98105
7.2 miles
Backyard ADU is a full-service ADU contractor managing every stage of accessory dwelling unit builds, including feasibility, permits, site surveys, foundations, construction, utility connections, and condo legal services.
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Cast Architecture
115 North 36th Street, Seattle, WA 98103
8.3 miles
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 c... read more
Microhouse
114 North 42nd Street, Seattle, WA 98103
8.6 miles
Microhouse is a Seattle-based ADU builder specializing in custom detached ADUs (DADUs). They guide homeowners through zoning, design, and construction. Seattle permitted 551 DADUs in 2022, with a 40% increase in 2023. Microhouse offers site assess... read more
Coates Design Architects
900 Winslow Way East, Bainbridge Island, WA 98110
13.6 miles
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
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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.