ADU Construction in Seattle

Residential remodeling in Seattle and the Eastside. Quality craftsmanship, clear timelines, and clean job sites.

ADU Construction - Professional home remodeling service by Kolmo Construction in Seattle

About Our ADU Construction Service in Seattle

Residential remodeling in Seattle, WA and the Eastside. Kolmo provides start-to-finish home renovation services across Seattle, Bellevue, Kirkland, Redmond, Renton, Issaquah, Shoreline, and nearby King & Snohomish County communities. Whether you’re updating one room or remodeling your entire home, we make the process simpler with clear planning, clean job sites, and workmanship built to last. We help with layout improvements, finish upgrades, and practical material selections that perform well in the Pacific Northwest. Common projects include kitchen and bathroom updates, flooring and trim, drywall and paint, lighting and fixture upgrades, and interior improvements that increase comfort and long-term value. You’ll get straightforward communication, realistic timelines, and a detailed plan before work begins. If you’re searching for residential remodeling near me, home renovation Seattle, or remodelers on the Eastside, Kolmo is ready to help. Request a quote for a clear scope, timeline, and a remodel you’ll actually enjoy living in.

Key Features & Benefits

Seattle + Eastside service area

Transparent estimates & timelines

Material and finish guidance

Clean job sites & respectful crews

Code-aware, detail-focused work

Quality craftsmanship & durable finishes

Flexible remodeling scopes (single room to full home)

On-site walkthroughs and progress updates

PNW-ready materials (moisture, wear, and maintenance friendly)

Our ADU Construction Process

1

Free Consultation & Walkthrough

We visit your home, learn your goals, take measurements, and confirm scope, constraints, and priorities.

2

Plan, Design & Materials

We help you finalize layout, finishes, and materials that match your style, budget, and Seattle-area home needs.

3

Detailed Quote & Schedule

You get a clear estimate and timeline. We align expectations before work starts, not after things go sideways.

4

Build & Project Updates

Our team completes demolition, construction, and installation with consistent communication and job-site cleanliness.

5

Final Walkthrough & Punch List

We verify details, address touch-ups, and hand off a finished space you’ll actually enjoy living in.

ADU Construction project completed by Kolmo Construction in Seattle - Example 1 showing quality craftsmanship

ADU Construction in Seattle: Common Questions

How much does an ADU cost to build in Seattle?

Kolmo's estimator prices a 600–1,000 sq ft detached ADU (DADU) in Seattle at about $199,000–$303,000 with standard finishes. Attached ADUs run about $77,700 for a 400 sq ft basement conversion to $219,100 for a 1,000 sq ft attached addition, and a garage-conversion ADU about $76,500–$99,800. Each is ±15%, priced 2026-10-28, and includes design, permits, foundation, framing, systems and finishes.

How long does ADU construction take in Seattle?

The full ADU process in Seattle takes 12–18 months: 1–3 months for design, 3–6 months for Seattle DCI permit approval, and 4–8 months for construction. Prefab ADUs can shorten construction to 2–3 months after permit approval.

What ADU types are allowed in Seattle?

Seattle allows detached ADUs (DADUs) up to 1,000 sq ft, attached ADUs, and garage conversions on most single-family lots. Seattle removed owner-occupancy requirements in 2019, allowing you to rent both the main home and the ADU simultaneously.

Ready to Start Your ADU Construction Project in Seattle?

Contact us today to schedule a free consultation and get a detailed quote. Our licensed team is ready to bring your vision to life with expert craftsmanship and attention to detail.

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Discover our full range of home remodeling and renovation services to transform every part of your Seattle home.