Basement Conversion in Washington
Red's Construction & Renovation
Federal Way, WA 98003
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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Exceptional Home Builders Seattle
1525 11th Avenue, Seattle, WA 98122
Exceptional Home Builders is a Seattle ADU contractor with 20+ years of experience. They offer full-service ADU construction, design-build, permitting, interior design, and renovations for backyard cottages, garage conversions, and basement units.
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Neil Kelly Washington
804 North Alberta Street, Seattle, WA 97217
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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Cascade Master Builders
209 River Park Ave, Unit 1, Wenatchee, WA 98801
Cascade Master Builders builds ADUs in Wenatchee & East Wenatchee, WA. Services include detached, attached, and garage/basement units. They handle permits, pre-approved plans, and financing guidance via HELOC for North Central Washington homeowners.
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Cascadia ADU
901 1st Street, Snohomish, WA 98290
Cascadia ADU builds attached, detached, garage & basement ADUs across King, Snohomish, Skagit & Chelan Counties, WA. Full-service design, permitting & construction completed in 8–10 weeks with 10+ years experience.
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Levite Construction CO
5608 17th Avenue Northwest, Seattle, WA 98107
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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J Hanby LLC
Edmonds, WA 98020
J Hanby LLC offers ADU and basement conversion services in the Eastside area. Specializing in detached ADUs, garage conversions, granny flats, and basement renovations, they help homeowners maximize property value and ROI.
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Better Builders
5606 California Avenue Southwest, Seattle, WA 98136
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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Rybak & Company LLC
19215 Southeast 34th Street, Camas, WA 98607
Rybak & Company LLC builds ADUs in Vancouver, Camas, Washougal & Portland Metro. Services include detached ADUs, garage conversions & in-law suites. Projects start at $175K–$250K+. Free estimates available.
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Northwest ADU Bellevue
278 106th Avenue Northeast, Bellevue, WA 98004
Northwest ADU builds custom detached ADUs, garage conversions & basement ADUs across Western Washington. Serving King, Pierce & Snohomish Counties with full-service ADU construction, build-ready plans & permit management.
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New Day Construction
15021 116th Place Northeast, Kirkland, WA 98034
New Day Construction is a licensed ADU builder in Bellevue, WA, with 21+ years of experience and 250+ projects. They build detached, attached, garage, basement, and custom ADUs, managing permits and design from start to finish.
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Harjo Construction
4900 15th Avenue Northwest, Seattle, WA 98107
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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Deane Home Services
17837 1st Avenue South, Normandy Park, WA 98148
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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Giant Builders Seattle
125 Boren Avenue South, Seattle, WA 98144
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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Huskies Construction
1201 Monster Road Southwest, Renton, WA 98057
Huskies Construction in Renton specializes in home additions, ADUs, and DADUs. Services include garage conversions, granny flats, in-law suites, backyard cottages, and room additions, helping homeowners expand living space or generate rental income.
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Other cities in Washington
What you need to know
Searching for top Basement Conversion ADU Contractors in Washington? Our directory highlights trusted local professionals who specialize in designing and building accessory dwelling units (ADUs).
Working with a qualified Basement Conversion ADU Contractor in Washington ensures your ADU project meets local building codes, zoning laws, and permit requirements. Whether you're planning a detached ADU, garage conversion, or backyard cottage, experienced Basement Conversion professionals can guide you through every step.
Washington homeowners are increasingly investing in ADUs to create additional living space, generate rental income, or support multigenerational living. The Basement Conversion experts featured here bring local expertise and proven experience to help make your project a success.
Browse our listings to find the best Basement Conversion ADU Contractors in Washington, and get started today.