ADU Construction Services

From feasibility study to keys in hand. Full-service ADU construction for Bellingham and Whatcom County homeowners.

Detached ADU (DADU)

Custom backyard cottages designed and built for Whatcom County lots. A completely separate structure with maximum privacy and rental potential.

$200K – $450K 6–12 months
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Attached ADU

Add a self-contained unit to your existing home — basement suites, side additions, or above-garage conversions.

$150K – $350K 4–9 months
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Garage Conversion

Convert your existing garage into a permitted ADU. The lowest-cost entry point for homeowners ready to start building equity.

$120K – $200K 3–6 months
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Basement ADU

Turn your unused basement into a rental-ready dwelling unit. Ideal for homes with existing below-grade space.

$100K – $200K 3–6 months
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ADU Design & Architecture

Custom floor plans and architectural design optimized for your lot, zoning, and budget. Our architect works within Whatcom County requirements.

Included with build 4–8 weeks
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ADU Permitting Services

Our dedicated permit specialist handles all zoning analysis, land use applications, and city/county coordination so you don't have to.

$1,500 deposit 4–12 weeks
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Sustainable ADU Construction

Energy-efficient, eco-conscious ADU construction. Heat pumps, high-performance envelopes, and designs that qualify for the 30% federal tax credit.

Built into every project Same as build
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Not Sure Where to Start?

Get a free feasibility study to confirm your property qualifies, then review our transparent pricing to understand the full investment. Or see the complete cost breakdown for Whatcom County ADUs.

Why Choose Us for Your ADU Project?

One Team, Start to Finish

You won't get handed off between companies. Carlos manages your build, Loren handles your permits, and our architect designs to your lot. One point of contact throughout.

GIS-Powered Feasibility

Our automated GIS pipeline checks your parcel against Whatcom County zoning, critical areas, watershed overlays, and transit routes before you spend a dollar.

2025 Law Experts

HB 1337 changed everything. We stay current on state mandates, Bellingham's December 2025 ordinance updates, and county comprehensive plan amendments.

Transparent Pricing

No surprise change orders. We provide detailed cost breakdowns by phase so you know exactly what you're paying for at every stage.

Check Your Property's ADU Potential

Get a free feasibility report based on Whatcom County GIS data and 2025 land use rules.

Get Your Free Feasibility Study