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.

What Does a Restoration Contractor Actually Do?

When a storm tears off part of your roof, a pipe bursts and floods your kitchen, or a fire damages your home, you hear the same advice from everyone: “Call a restoration contractor.” But what exactly does a restoration contractor do? And how are they different from a regular contractor or handyman?

If you’re dealing with property damage for the first time, understanding what a restoration contractor handles — and why they exist — can save you time, money, and a lot of stress during the recovery process.

Restoration Contractors vs. General Contractors

A general contractor builds and remodels. They work from blueprints, follow a planned schedule, and manage new construction or renovation projects. A restoration contractor does something fundamentally different: they return a damaged property to its pre-loss condition after an unexpected event like a storm, flood, or fire.

This distinction matters because restoration work operates under a completely different set of rules. There’s no planned timeline — the emergency dictates the schedule. The scope of work is defined by the damage, not by a design. And most importantly, the work is funded through an insurance claim, which means the contractor must navigate a complex process of documentation, adjuster coordination, and supplement filings that general contractors rarely encounter.

A skilled restoration contractor is part builder, part insurance specialist, and part project manager — handling all three simultaneously.

What Restoration Contractors Handle

Emergency response and mitigation. When your property is damaged, the first priority is stopping the damage from getting worse. A restoration contractor provides emergency services like roof tarping, board-up, water extraction, structural shoring, and debris removal. This emergency mitigation is documented and billed directly to your insurance claim. Most restoration contractors offer 24/7 emergency response because storms, fires, and floods don’t wait for business hours.

Damage documentation and assessment. Before any repairs begin, a restoration contractor conducts a thorough inspection and creates detailed documentation of all damage. This includes professional photography, measurements, moisture readings (for water damage), and written reports formatted in a way insurance adjusters recognize. This documentation is the foundation of your insurance claim — and it’s often the difference between a fully covered repair and a denied or underpaid claim.

Insurance claims coordination. This is where restoration contractors fundamentally differ from general contractors. A restoration contractor manages the entire insurance claims process on your behalf: filing the initial claim, attending the adjuster inspection, reviewing the insurance estimate, filing supplements for missed items, and coordinating payment. They speak the language of insurance — including Xactimate estimating software, which is the industry standard used by most major insurers.

Complete property repair and rebuild. After the claim is approved, the restoration contractor performs all necessary repairs to return your property to pre-damage condition. For a storm damage project, this might include roof replacement, siding repair, gutter installation, window replacement, interior drywall and painting, and exterior finishing. For water damage, it includes structural drying, mold remediation, drywall replacement, flooring, and painting. For fire damage, it includes structural rebuild, smoke and soot cleaning, odor removal, and complete interior restoration.

Final walkthrough and claim closure. When the work is complete, a restoration contractor does a final inspection with the homeowner, addresses any remaining items, submits completion documentation to the insurance company (to release any held depreciation), and closes out the claim.

The Insurance Side: Why It Matters

The insurance component is what makes restoration contracting a specialty. A contractor who doesn’t understand insurance processes can cost homeowners thousands of dollars in unrealized claim value. Here’s how:

An inexperienced contractor might provide a basic estimate that covers the obvious damage but misses code upgrades, hidden damage, matching requirements, and overhead and profit that your policy covers. The insurance company pays based on the documented scope — if the documentation is incomplete, the payout is incomplete.

A restoration specialist, on the other hand, knows how to use Xactimate (the estimating software adjusters use), understands line items and pricing databases, and knows when and how to file supplements. They ensure the claim reflects the true cost of restoration — not a lowball estimate based on incomplete documentation.

When You Need a Restoration Contractor (Not a Handyman)

Not every repair requires a restoration contractor. A leaky faucet or a broken window from a baseball can be handled by a handyman or general contractor. But you need a restoration contractor when:

The damage is covered by insurance. If you’re filing a claim, you want a contractor who understands the claims process and can maximize your payout.

Multiple trades are involved. Storm damage might require roofing, siding, gutters, painting, and interior work. A restoration contractor handles all of these under one scope of work — one point of contact instead of five separate contractors.

Emergency response is needed. If your home is exposed to the elements or actively flooding, you need a contractor with 24/7 emergency capability and the equipment to mitigate damage immediately.

Documentation is critical. Insurance claims require specific, detailed documentation. A restoration contractor creates this documentation as part of their standard process.

What to Look for in a Restoration Contractor

If you need a restoration contractor, choose one with demonstrated insurance restoration experience — not a roofer or handyman who occasionally handles a claim. Look for familiarity with Xactimate estimating, a track record of successful insurance claims in your area, the ability to handle multiple trades in-house, 24/7 emergency availability, proper licensing and insurance in your state, and strong reviews from homeowners who’ve been through the claims process.

How Prolific Design-Build and Restoration Handles Restoration

At Prolific Design-Build and Restoration, insurance restoration is all we do. We don’t do remodels or new construction — we specialize exclusively in restoring properties after storm damage, water damage, and fire damage. Every project goes through our proven process: emergency response, thorough documentation, insurance coordination, premium restoration, and final walkthrough.

With 500+ completed insurance restoration projects across King County, we’ve built our entire business around getting homeowners back to normal as quickly and completely as possible — while maximizing every dollar their insurance policy provides.

Dealing with property damage? Call (425) 800-4775 for a free inspection and insurance consultation. We’ll assess the damage, explain your options, and handle the entire restoration process from emergency response to final repair. Serving Issaquah, Bellevue, Renton, Sammamish, Kirkland, Redmond, Kent, Auburn, Federal Way, Maple Valley, and all of King County.

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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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