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.

Prolific Protection Plan — Annual Home Exterior Maintenance Membership

Prolific Protection Plan — Annual Home Exterior Maintenance Membership

The Prolific Protection Plan is our annual membership program designed to keep your home’s exterior in peak condition — and to make insurance claims seamless if storm damage ever strikes. Members receive annual professional inspections, priority emergency response, insurance claims assistance, and exclusive repair discounts.

Why Join the Prolific Protection Plan?

King County homeowners face severe weather year-round — windstorms, heavy rain, ice, and occasional hail. Most homeowners don’t know their roof or siding is damaged until water is coming through the ceiling. By then, the damage is worse, the repair is more expensive, and the insurance claim is harder to document.

The Prolific Protection Plan solves this. We inspect your home annually, catch problems before they become emergencies, and keep documented records of your home’s condition. When a storm does hit, you have a contractor who already knows your home, already has pre-storm documentation on file, and responds to your call first.

What’s Included in Your Membership

Annual Comprehensive Roof Inspection

A thorough inspection of your entire roof system — shingles, flashing, gutters, fascia, soffit, vents, skylights, and underlayment. We provide a written report with photos documenting the current condition of every component. This documentation becomes invaluable if you ever need to file an insurance claim.

Annual Exterior Assessment

Complete inspection of your siding, exterior paint, trim, windows, doors, and foundation perimeter. We identify deterioration, damage, moisture intrusion, and maintenance needs before they become costly repairs.

Pre-Storm Photo Documentation on File

This is one of the biggest advantages of membership. Insurance companies approve claims faster when you can prove the pre-storm condition of your home. We keep dated, high-resolution photos of your roof and exterior on file. When damage occurs, we have before-and-after documentation ready — which means faster approvals and higher payouts.

Priority Emergency Response — 24 Hours

Members get priority scheduling for emergency repairs. When a storm hits King County and every contractor’s phone is ringing, Protection Plan members go to the front of the line. We respond within 24 hours to secure your home and begin the claims process.

Full Insurance Claims Assistance

Members receive complete insurance claims support at no additional charge. We handle documentation, claim filing, adjuster coordination, supplements, and appeals. Because we already have your home’s records on file, the claims process is faster and smoother for members.

10% Off All Repairs & Restoration

Members receive 10% off all repair and restoration work — including insurance deductible payments, out-of-pocket repairs, and maintenance work not covered by insurance. This discount applies to roofing, siding, painting, gutters, and all exterior services.

100% Membership Fees Credited Toward Major Projects

If you undertake a major project with us — full roof replacement, complete siding installation, or whole-house exterior painting — 100% of your accumulated membership fees are credited toward the project cost. Your membership literally pays for itself.

Transferable Membership

Selling your home? Your Protection Plan membership transfers to the new owner, adding value to your property. Buyers appreciate knowing the home has been professionally maintained with documented records.

How It Works

  1. Sign up — Call (425) 800-4775 or fill out the form below to enroll
  2. Initial inspection — We perform your first comprehensive roof and exterior inspection within 2 weeks of enrollment
  3. Documentation on file — Your home’s condition is photographed and recorded in our system
  4. Annual maintenance — We contact you each year to schedule your inspection (spring or fall — your choice)
  5. Storm response — If damage occurs, call us and you’re at the front of the line with documentation ready to go

Who Is the Protection Plan For?

The Prolific Protection Plan is ideal for King County homeowners who want peace of mind knowing their home’s exterior is professionally monitored, documented, and maintained. It’s especially valuable for homeowners with roofs over 10 years old, homes in heavily wooded areas (tree fall risk), properties that have experienced previous storm damage, or anyone who wants to maximize their insurance coverage if damage occurs.

Serving All of King County

The Prolific Protection Plan is available throughout King County including Issaquah, Bellevue, Sammamish, Renton, Kirkland, Redmond, Kent, Auburn, Federal Way, Maple Valley, Covington, Enumclaw, Black Diamond, and surrounding communities.

Enroll Today

Call (425) 800-4775 to enroll in the Prolific Protection Plan or to learn more about membership benefits. Your first inspection is scheduled within 2 weeks of enrollment — because protecting your home starts now.

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

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