Seattle ADU is a Seattle-based contractor specializing in accessory dwelling units, including detached ADUs, garage conversions, attached ADUs, and JADUs. They manage design, permitting, and construction for homeowners seeking additional living space.
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Giant 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.
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Twin Brothers Group is a licensed framing contractor in Washington State specializing in ADU, DADU, garage conversions, and home additions across King and Snohomish County, serving Seattle-area GCs and owner-builders.
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Armada Design & Build Inc., Bellevue, WA, offers full-service residential design-build since 2011. Specializing in remodels, home additions, and custom builds across Puget Sound, they deliver turnkey solutions with in-house design and quality craftsmanship.
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Northwest ADU is a trusted ADU builder in Mill Creek, WA, offering full-service accessory dwelling unit construction, including detached ADUs, garage conversions, and basement conversions, with expert permit and zoning support.
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Red's Construction & Renovation serves Federal Way & South King County, WA, specializing in ADU construction including detached, attached, garage conversions & basement units. Costs range from $50K–$300K+. Licensed, insured, transparent pricing.
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Deane Home Services builds ADUs in South King County, WA, including garage conversions, basement remodels, and detached backyard cottages. Licensed, bonded & insured. Serving Kent, Renton, Federal Way & more.
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Haas Development & Construction offers ADU & DADU construction in Greater Seattle. They handle planning, permits, design, and builds for attached & detached units, including prefab DADU plans, helping homeowners add rental income or family housing.
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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.
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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 ensure smooth project execution.
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Brutsky Builds is a licensed ADU contractor in Bellevue offering full-service accessory dwelling unit construction. Services start from $210,000, covering design, permitting, and build completion in ~6 months.
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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 & permit-ready plans included.
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NW 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 ADUs.
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Northwest ADU is a full-service ADU contractor in Western Washington specializing in detached ADUs, garage conversions, and basement conversions. Serving Pierce, King, and Snohomish Counties, projects range from $180K–$350K+, taking 6–10 months.
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Avio Homes is a Seattle-based ADU contractor specializing in detached ADUs, backyard cottages, and in-law suites. Serving Seattle, Tacoma, and Olympia, they handle design, permitting, and construction with local zoning expertise.
read moreSeaTac, Washington is a unique city shaped largely by its proximity to Seattle-Tacoma International Airport. This means that ADU contractors working in SeaTac must navigate not only standard King County and city zoning regulations, but also Federal Aviation Administration (FAA) height restrictions and noise compatibility guidelines. These aviation-related constraints can directly impact the design and construction of Accessory Dwelling Units, making it essential to hire an experienced ADU contractor who understands the local landscape.
SeaTac operates under its own municipal code, separate from unincorporated King County. Homeowners looking to build an ADU in SeaTac must comply with the SeaTac Municipal Code Title 15, which governs land use and zoning. Key considerations include:
One of the most distinctive challenges for ADU contractors in SeaTac is addressing aircraft noise. The city falls within the Airport Influence Area, and many properties are subject to significant noise levels measured in Day-Night Average Sound Levels (DNL). Contractors must often incorporate sound attenuation measures such as enhanced insulation, double-pane or triple-pane windows, and specialized ventilation systems to meet habitability standards. Some properties may even qualify for the Port of Seattle's Residential Sound Insulation Program, which can offset certain construction costs.
Working with an ADU contractor who has direct experience in SeaTac provides significant advantages. A knowledgeable local contractor will be familiar with:
Despite its unique regulatory environment, SeaTac presents a strong opportunity for ADU development. The city's location along the Link Light Rail corridor and its proximity to major employment hubs make rental ADUs highly attractive. With Washington State's ADU-friendly legislation continuing to evolve, now is an excellent time to consult with a qualified SeaTac ADU contractor to explore your options, maximize your property's potential, and ensure full compliance with all local, state, and federal requirements.