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.

Emergency Roof Repair After a Windstorm: King County Homeowner’s Guide

What to Do When Wind Damages Your Roof

King County’s windstorms are no joke. When a Pacific weather system rolls through with 50-70 mph gusts, roofs take the brunt of it. Missing shingles, lifted flashing, fallen trees on rooflines, and exposed decking are all scenarios we respond to regularly at Prolific Design-Build and Restoration.

Here’s your step-by-step guide for handling roof damage after a King County windstorm.

Assess Safely from the Ground

Never climb onto a damaged roof. Structural integrity may be compromised, wet surfaces are slippery, and additional wind gusts can make the situation dangerous. Instead, walk around your home at ground level and look up. Note any visible missing shingles, dangling gutters, fallen branches on the roof, or debris in the yard that may have come from your roof.

Inside your home, check ceilings for water stains, drips, or bulging — these indicate active leaks. If you see water dripping near electrical fixtures, turn off power to those circuits at the breaker panel and call a professional immediately.

Emergency Tarping and Temporary Repairs

If your roof has an active breach — missing shingles exposing decking, or worse, a hole from fallen tree impact — temporary waterproofing is critical. Professional emergency tarping involves securing heavy-duty tarps over the damaged area with proper weighting and fastening to prevent wind from lifting them.

Prolific maintains emergency tarping crews that respond across King County within 30-60 minutes. We carry commercial-grade tarps, lumber for bracing, and the equipment to work safely at height in adverse conditions. This emergency response is covered by your homeowner’s insurance as damage mitigation.

Full vs. Partial Roof Replacement

After emergency stabilization, the question becomes: repair or replace? If wind damage is limited to a section of the roof and the rest is in good condition, a localized repair may be appropriate. However, if your roof is approaching the end of its expected lifespan (typically 20-30 years for asphalt shingles in the Pacific Northwest), wind damage may be the catalyst for a full replacement — and insurance may cover a significant portion.

Prolific provides honest roof assessments. We don’t push full replacements when repairs will do, and we don’t patch roofs that need replacing. Our team includes licensed roofers who work alongside our general contracting crew, so whether it’s a repair or replacement, it’s handled in-house.

Working With Insurance for Roof Claims

Roof damage claims have specific nuances. Insurance adjusters look for wind patterns in the damage — directional shingle loss, lifted edges facing the prevailing wind — to confirm weather-related cause. They’ll also note the roof’s age and condition to assess pre-existing wear versus storm damage.

Having a knowledgeable contractor present during the adjuster’s roof inspection is invaluable. We can point out damage that’s not visible from the ground, identify compromised areas that may leak later, and ensure the scope of work in the estimate reflects reality.

Don’t Wait — Every Rainstorm Compounds the Damage

In King County, a damaged roof is a ticking clock. Our next rainstorm is never far away, and every drop of water that enters through a compromised roof causes cascading damage to insulation, framing, drywall, and personal property below. What starts as a $3,000 roof repair can become a $20,000 restoration project if water intrusion goes unchecked.

If your King County roof has been damaged by wind, call Prolific Design-Build and Restoration at (425) 800-4775. We provide emergency tarping 24/7, free roof damage assessments, and complete repair or replacement with full insurance claims management.

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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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