ADU & DADU Contractor — King County, WA

Add a Legal Dwelling Unit
to Your King County Property

From permit application to final walkthrough — Prolific handles design-build ADU and DADU projects across Federal Way, Issaquah, Renton, Kent, and greater King County.

$180KAverage ADU Cost (King County)
6–12moTypical Timeline Permit to Move-In
$1,800+Monthly Rental Income Potential
3–5yrAverage ROI Payback Period

What We Build

Every ADU project is custom-designed for your lot, your goals, and King County code.

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Detached ADU (DADU)

A standalone dwelling in your backyard. Most flexible for rental or multigenerational living. Requires setback compliance and separate utility connections.

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Attached ADU

Connected to the primary home via a shared wall. Lower cost than detached, faster permitting. Ideal for in-law suites or long-term rental income.

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Junior ADU (JADU)

Converted from existing interior space — garage, basement, or bonus room. Lowest cost entry point. Limited to 500 sq ft per King County code.

The King County Permitting Process

Prolific handles every step. Most homeowners have never pulled a permit — we've done hundreds.

1

Site & Zoning Review

We verify your parcel's zoning, setbacks, lot coverage, and utility capacity before design starts. Catches 80% of project-killers on day one.

2

Design & Engineering

Architectural plans drawn to King County standards. Structural engineering included where required. Typical design phase: 3–6 weeks.

3

Permit Submission

We submit to King County DPER or the applicable city (Federal Way, Renton, Issaquah, Kent). Electronic submission with full plan set.

4

Review & Corrections

County review typically takes 6–12 weeks. We respond to all correction requests and manage the back-and-forth until permit issuance.

5

Build & Final Inspection

Construction with milestone inspections. Final inspection and certificate of occupancy required before the unit can be rented or occupied.

Cost Ranges for King County ADUs

Rough estimates — every project varies by site, size, and finish level. Free estimate available after a site visit.

ADU TypeSize RangeTypical Cost Range
Junior ADU (JADU)Up to 500 sq ft$60,000 – $120,000
Attached ADU400–800 sq ft$120,000 – $200,000
Detached ADU (DADU)400–1,200 sq ft$160,000 – $320,000

Ready to Add a Unit to Your Property?

Free site consultation. We'll tell you what's possible on your lot before you spend a dollar.

Get Your Free ADU Estimate

Prolific's Differentiator

While We're Restoring Your Home, Let's Make It Better Than Before

Most contractors patch the damage and leave. We use the restoration as a launchpad — pairing insurance coverage with a remodel that upgrades what you had.

Storm + Remodel

Federal Way — Hail Damage + Kitchen Upgrade

Insurance covered the roof and siding. While we had the crew on-site, the homeowners financed a kitchen remodel they'd been putting off for years. One mobilization, two wins.

Water + Addition

Renton — Burst Pipe + Primary Bath Expansion

A burst pipe triggered an insurance claim for the subfloor and drywall. We rebuilt the bathroom larger than it was — same timeline, carrier paid the base, owner paid the delta.

Fire + Rebuild

Issaquah — Garage Fire + ADU Conversion

Garage total loss became a permitted two-car garage with a studio ADU above. Insurance rebuilt what burned. The ADU now generates rental income to offset the mortgage.

Insurance Claim? We Handle Everything.

Your Insurance Company Has Adjusters.
Now You Have Us.

STORM DAMAGE RESPONSEthousands more for homeowners just like you.

Bellevue Home Restoration and Remodeling: Trusted Contractor for the Eastside’s Premier City

Bellevue Demands a Higher Standard

Bellevue is the economic center of the Eastside and one of the most affluent cities in Washington State. From historic Enatai waterfront homes to modern construction in West Bellevue, from established neighborhoods in Crossroads to luxury estates in Somerset and Meydenbauer — Bellevue’s diverse housing stock requires a contractor who can handle everything from complex insurance restorations to high-end remodeling.

Prolific Design-Build and Restoration is proud to serve Bellevue homeowners with comprehensive restoration and remodeling services. We understand that Bellevue homeowners expect premium craftsmanship, clear communication, and a contractor who respects both their home and their time.

Restoration Services for Bellevue Homes

Water damage restoration. Bellevue homes face water damage from varied sources — aging plumbing in older neighborhoods, construction defects in newer builds, storm runoff in hillside areas, and appliance failures across all types. Our emergency water damage restoration includes rapid water extraction, structural drying, and complete rebuilding.

Storm and wind damage. Bellevue’s mature tree canopy — especially in neighborhoods like Bridle Trails, Tam O’Shanter, and Phantom Lake — creates significant storm damage risk. Fallen trees, roof damage, broken windows, and siding failures all require prompt professional response. See our storm damage restoration guide.

Fire damage restoration. From kitchen fires to electrical fires in older homes, we provide full fire damage restoration including emergency board-up, smoke and soot cleanup, structural rebuilding, and odor elimination.

Mold remediation. Bellevue’s climate and older housing stock make mold a persistent concern. We handle professional mold remediation from inspection through clearance testing and reconstruction.

Remodeling in Bellevue

Bellevue’s housing market rewards smart remodeling investments. With some of the highest per-square-foot values in the region, quality renovations deliver strong returns.

Kitchen remodeling is the highest-impact renovation for Bellevue homes. Whether you’re opening up a closed-off 1980s kitchen or upgrading a builder-grade new construction kitchen to premium finishes, our kitchen remodeling guide covers the full scope of what Eastside homeowners are doing.

Bathroom renovations are especially popular in Bellevue, where older homes often have dated primary bathrooms that don’t match the home’s overall value. Our bathroom remodeling guide covers current trends and costs.

ADU and DADU construction. Bellevue has been actively expanding its ADU-friendly zoning, and demand is strong for both rental income units and family-use accessory dwellings. Our ADU construction guide covers permits, costs, and what to expect in the Bellevue permitting process.

Whole-home renovations for homeowners who want to modernize their existing Bellevue home rather than sell and buy new. We handle multi-room projects that transform the entire living experience while you stay in your home.

Navigating Bellevue Building Permits

The City of Bellevue has some of the most rigorous permitting requirements on the Eastside. Projects involving structural changes, plumbing, electrical, or exterior modifications all require permits and inspections. We handle all permit applications, plan submissions, and inspection scheduling with the Bellevue Development Services Center — so you don’t have to navigate the bureaucracy.

For larger projects, Bellevue may require design review, tree preservation plans, or stormwater management plans. Our team has experience with all of these requirements and builds them into our project timelines from the start.

Insurance Claims in Bellevue

Bellevue’s high home values mean insurance claims involve larger numbers and more complex negotiations. Adjusters scrutinize high-value claims more carefully, and the difference between a well-documented claim and a poorly documented one can be tens of thousands of dollars.

We specialize in high-value home insurance restoration and work directly with adjusters to ensure every element of damage is properly documented and included in the claim. Our insurance claims guide is a must-read for Bellevue homeowners.

Your Bellevue Contractor

Prolific Design-Build and Restoration delivers premium restoration and remodeling services to Bellevue homeowners across every neighborhood — from Crossroads to Somerset, Factoria to West Bellevue, Bridle Trails to Newport Shores.

Call (425) 800-4775 or request a free consultation. Black-owned and Latino-owned — bringing 5-star craftsmanship to Bellevue’s finest homes.

Related: Sammamish Restoration & Remodeling | Roof Repair & Replacement | Storm Season Prep Checklist

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We respond within 2 business hours — same day for emergencies.

A member of our team will reach out shortly to schedule your free estimate or inspection. Here's what to have ready when we call:

What to Have Ready

  • Photos of the damage or area of concern (phone photos are fine)
  • Your insurance carrier name and claim number (if applicable)
  • Best time and number to reach you
  • A rough idea of when the damage occurred or project timeline
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Prolific Design-Build & Restoration — Federal Way, WA

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