ADU Construction
Seattle

Add rental income, multi-generational living, or a home office. Washington ADU laws make it easier than ever.

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5.0 Google · 30 Reviews
100+ ADUs Built
Licensed, Bonded & Insured · WA #606007438
Full Permit Service
5-Year Warranty

Rated by Seattle Homeowners

5.0

· 30 reviews

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"The work this team provides is exceptional!"

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ADU Builder Seattle: Why Homeowners Choose Us

$2,500+
Average Monthly Rental Income
Seattle ADU rentals command some of the highest rates in the Pacific Northwest
$150K+
Average Property Value Increase
ADUs significantly increase appraised property value in the Greater Seattle Area
4–6yr
Typical Payback Period
Most ADUs pay for themselves within 4–6 years through rental income
ADU construction Seattle

Seattle ADU Builders: Your Local Specialists

Washington's ADU laws have never been more favorable for homeowners. ADU construction Seattle WA residents invest in is now more accessible — and more profitable — than ever, thanks to streamlined permitting and relaxed setback requirements. Homeowners searching for ADU contractors near me choose Da Vinci for our expertise.

Full Permit & Entitlement Service
We handle every aspect of the Seattle permitting process — from feasibility analysis to final sign-off.
Design-Build Under One Roof
Architect, designer, and builder — all in-house. No coordination headaches, cleaner communication, faster delivery.
100+ ADUs Completed
We've navigated every type of ADU project in Seattle and surrounding cities. Your project benefits from that experience.
Get Free ADU Feasibility Analysis

ADU Construction Seattle: Types We Build

Detached ADU Seattle
Most Popular

Detached ADU in Seattle

A fully independent unit on your property — the most valuable ADU type. Ideal for rental income or extended family. ADU companies near me recommend detached units for maximum ROI.

From $180,000
Garage conversion ADU
Best Value

Seattle ADU Garage Conversion

Transform your existing garage into a livable ADU. Lower ADU Seattle cost, faster permitting, excellent ROI for the Greater Seattle Area.

From $120,000
Attached ADU addition
Popular Option

Attached ADU

An addition to your main home with its own entrance. Efficient use of space with shared wall construction savings.

From $150,000
Junior ADU JADU
Quickest to Permit

Junior ADU (JADU)

Convert an existing room within your home into a studio-style unit with its own exterior entrance. Max 500 sq ft.

From $60,000
Second story ADU
Premium Option

Second Story ADU

Add a second story to your garage or home for a premium ADU that maximizes your property footprint.

From $220,000
ADU home office studio
Lifestyle Upgrade

Studio / Home Office

A dedicated creative studio, home office, gym, or flex space. Adds value and versatility to your property.

From $80,000

ADU Contractors Seattle: Our Build Process

1

Feasibility Analysis

We assess your lot, existing structures, setbacks, and utilities to determine what's possible — free of charge.

2

Design & Permitting

Our architect creates plans and submits to the City of Seattle. We track every step of the approval process.

3

Construction

Our licensed team handles all trades — foundation, framing, plumbing, electrical, insulation, drywall, finishes.

4

Final Inspection & Keys

City final inspection passed. We hand over the keys with your Certificate of Occupancy and warranty documentation.

ADU in Seattle: Questions Answered

ADU costs in Seattle range from $60,000 for a Junior ADU to $350,000+ for a premium detached ADU. Garage conversions run $120K–$180K. Most clients see full ROI within 4–6 years through rental income.
Permitting takes 3–6 months in Seattle. Construction typically takes 3–5 months. Total timeline from start to move-in is typically 6–12 months.
Yes — Seattle allows ADUs to be rented to unrelated tenants. Average rental rates range from $2,000–$3,500/month depending on size and location. ADUs cannot be sold separately from the main home.
Washington law now allows 4-foot rear and side setbacks for most ADUs. Seattle follows state minimums. We conduct a free feasibility analysis to determine exactly what's buildable on your lot.
Yes — we work with ADU-specific lenders offering construction loans, HELOC financing, and cash-out refinance options. Several programs allow $0 out-of-pocket if you have sufficient home equity.

Free ADU Feasibility Analysis

Find out exactly what you can build on your property — no obligation, no cost.

No obligation · We respond within 24 hours

Call Now: (360) 361-8632