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.

Wind Damage Roof Repair King County

🌬️ Windstorm Damage? We Respond 24/7

Emergency tarping, full roof repair, and complete insurance claims handling.

Wind Damage Roof Repair & Restoration in King County, WA

Pacific Northwest windstorms are no joke. Atmospheric rivers, Pineapple Express events, and fall/winter storms regularly bring 50-70 mph gusts that rip shingles off roofs, topple trees onto homes, and drive rain into exposed structures. When wind damage hits your King County home, Prolific Design-Build and Restoration is on-site fast with emergency tarping and complete insurance restoration.

We handle the entire process from emergency response through final repair — including every step of your insurance claim. Our team documents damage using Xactimate (the same software your insurance adjuster uses), meets with adjusters on-site, and manages supplements so you get the full coverage you’re entitled to.

Common Wind Damage We Repair

  • Blown-off or lifted shingles — wind gets under edges and peels them back
  • Ridge cap damage — the most wind-vulnerable part of any roof
  • Tree impact damage — fallen trees and large branches crushing roof sections
  • Fascia and soffit damage — wind rips these components off, exposing your attic
  • Flashing separation — wind lifts metal flashing around chimneys, vents, and valleys
  • Siding blown off — vinyl and fiber cement siding torn away by high winds
  • Gutter detachment — gutters pulled away from fascia boards by wind and debris
  • Water intrusion — once the roof is compromised, rain follows immediately

Our Emergency Wind Damage Response

  1. 24/7 Emergency Call — Call us any time. We answer day or night during storms.
  2. Emergency Tarping — We get a tarp on exposed areas to stop water intrusion immediately.
  3. Full Damage Assessment — Comprehensive inspection with photo documentation of all damage.
  4. Insurance Claim Filed — We help you file with complete documentation for fastest approval.
  5. Adjuster Coordination — We meet your adjuster on-site and walk through every damage point.
  6. Complete Repair — Roof, siding, gutters, interior water damage — we handle it all.

PNW Storm Season: October through February

King County’s windstorm season runs from late October through February, with peak damage events in November and December. Atmospheric rivers can sustain 40-60 mph winds for 12+ hours. Don’t wait until the next storm to find a contractor — save our number now: (253) 444-8822

Wind Damage? Call Now — We Respond 24/7

Emergency tarping available today. Insurance claims handled start to finish.

📞 Call (253) 444-8822

Insurance Carriers We Work With

State Farm, Allstate, PEMCO, USAA, Farmers, Liberty Mutual, Safeco, Nationwide, American Family, Hartford, Travelers, Erie — and every other carrier in Washington State. We speak Xactimate and submit clean estimates that get approved fast.

Service Areas: Seattle, Bellevue, Kent, Renton, Federal Way, Auburn, Tacoma, Burien, Tukwila, SeaTac, Maple Valley, Covington, Sammamish, Issaquah, Mercer Island, and all of King County, WA.

Licensed & Insured | WA Contractor License: PROLISN788QN

Dealing with storm damage? We're here — call now or submit your info and we'll call you within the hour.

We Got Your Request

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

📋 Get a Free Estimate