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.
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Gordon T. Jacob is a family-run ADU builder and home remodeling contractor in South Puget Sound. Specializing in detached ADUs, backyard cottages, middle housing, and full home renovations in the Tacoma area.
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FTS Excavation offers full-service ADU site development in South Puget Sound, Western Washington. Services include grading, utilities, septic systems, foundation excavation & permits. Certified, reliable ADU contractor for backyard homes & accessory dwelling units.
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The 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 value.
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ModernSpace ADU Construction is a certified ADU builder serving Redmond, offering tailored accessory dwelling unit services. Competitive pricing, no hidden fees, and a satisfaction guarantee make them a trusted local choice.
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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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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.
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Marksymov Brownstone LLC is a licensed Seattle ADU contractor offering basement, garage & attic conversions. They handle design, permits & construction, ensuring code compliance across Seattle, Bellevue & Kirkland.
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H26 Builders is a Seattle ADU contractor offering attached ADUs, detached ADUs, and garage conversions. Services include design consultation, permitting support, and project management to help homeowners add functional living or rental space.
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Seattle's trusted DADU & ADU builder offers custom builds, ADU conversions, and prefab cabins. Transparent pricing, expert guidance, and hands-on construction help homeowners add lasting value with backyard cottages and granny flats.
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Neil Kelly Washington offers ADU design and build services in the Northwest, including detached ADUs, garage conversions, and attached units. Their team navigates local permits, balances design with functionality, and helps homeowners add value through custom accessory dwelling units.
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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.
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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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Tacoma 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.
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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.
read moreMercer 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.
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:
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:
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.
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.