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 moreShoreline, Washington is one of the Puget Sound region's most progressive cities when it comes to housing density and accessory dwelling units. Located just north of Seattle along the I-5 corridor, Shoreline has actively embraced ADU development as part of its broader strategy to increase housing availability near its two future light rail stations — Shoreline South/148th and Shoreline North/185th — both part of Sound Transit's Lynnwood Link Extension. This transit-oriented growth mindset makes working with experienced ADU contractors in Shoreline, WA more important than ever for homeowners looking to add value and rental income to their properties.
Before breaking ground, homeowners and ADU builders in Shoreline must navigate the city's specific zoning and permitting requirements. Shoreline allows both attached ADUs (AADUs) and detached ADUs (DADUs) in most single-family residential zones. Key regulations include:
Permits are issued through the City of Shoreline's Development Services department, and experienced local ADU contractors will be familiar with the city's online permitting portal and inspection processes, helping to avoid costly delays.
Hiring a local ADU contractor in Shoreline, Washington offers significant advantages over working with a general contractor unfamiliar with the area. Local professionals understand the city's specific soil conditions, stormwater management requirements, and the nuances of building near protected critical areas — which are present in parts of Shoreline due to its proximity to Puget Sound and various wetlands. A knowledgeable contractor will also be up to date on any recent amendments to Shoreline's Municipal Code that affect ADU construction.
A full ADU construction project in Shoreline typically involves site evaluation, architectural design, permit application, foundation work, framing, electrical, plumbing, insulation, and finishing. Costs can vary widely based on unit size and complexity, but homeowners should generally budget between $150,000 and $300,000 for a detached ADU in the greater Seattle metro area. The investment often pays off through rental income, especially given Shoreline's strong rental demand driven by proximity to Seattle and future light rail access.