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.

Mold Remediation Bellevue, WA

Mold Remediation in Bellevue, WA | Safe & Certified Removal

Bellevue’s diverse neighborhoods—from Crossroads and Factoria to Somerset and Newport Hills—all share the same Pacific Northwest mold risk. Heavy rainfall, moisture infiltration, and varying home ages create conditions where mold thrives. Prolific Design-Build and Restoration provides professional mold remediation across all Bellevue neighborhoods, addressing moisture problems and restoring healthy indoor environments.

Why Bellevue Homeowners Choose Prolific

Bellevue’s housing stock spans from 1970s construction with aging waterproofing to modern builds with contemporary moisture management systems. This means we encounter every mold scenario: crawl space colonization in older Factoria and Crossroads homes, attic mold in properties with ventilation issues, basement moisture in Somerset properties, and water damage mold in homes following plumbing or roof failures.

Mold represents both health and property concerns. Respiratory symptoms, allergic reactions, and property value impact affect many Bellevue homeowners. Professional remediation isn’t optional—it’s essential for home protection and family health.

We’re licensed and insured for mold remediation. We’ve successfully addressed mold challenges across every Bellevue neighborhood, understanding local building codes, moisture patterns, and home-specific vulnerabilities.

Our Mold Remediation Process

Step 1: Thorough Assessment — We inspect your entire home, identify visible mold, conduct air quality testing, and locate moisture sources. You’ll understand the scope and severity.

Step 2: Detailed Remediation Strategy — Our plan addresses mold removal, underlying moisture causes, and prevention measures. Clear communication ensures you understand everything we’ll do.

Step 3: Professional Removal — Using EPA-approved methods, we safely remove mold, contain spores, dispose of contaminated materials properly, and treat affected areas.

Step 4: Moisture Source Elimination — We fix root causes: roof leaks, gutter problems, crawl space ventilation, sump pump installation, or waterproofing upgrades.

Step 5: Documentation & Verification — Post-remediation testing confirms success. You receive documentation for insurance, health, and future reference.

Why Choose Prolific for Bellevue Mold Remediation

Licensed mold remediation specialists with insurance coverage and bonding. Xactimate certification provides insurance documentation. Extensive Bellevue neighborhood experience across Crossroads, Factoria, Somerset, Newport Hills, and surrounding areas. We work with homeowner insurance companies to maximize coverage and minimize your costs.

Service Areas from Bellevue

Bellevue neighborhoods including Crossroads, Factoria, Somerset, Newport Hills, plus surrounding Redmond, Sammamish, Kirkland, Issaquah, and broader Eastside communities.

Frequently Asked Questions

What causes mold in Bellevue homes?

Primary causes are roof leaks, gutter failures, crawl space moisture, inadequate attic ventilation, and plumbing leaks. Bellevue’s rainfall exacerbates any existing moisture problem. We identify your specific cause and address it permanently.

Is mold dangerous to my family?

Mold exposure can trigger respiratory issues, allergies, and asthma aggravation, particularly in children, elderly, and immunocompromised individuals. Identifying and removing mold protects family health.

How much does mold remediation cost in Bellevue?

Cost depends on mold extent, affected materials, and moisture source complexity. A small bathroom mold removal might cost $500-1000. Major remediation in crawl spaces could exceed $5000-10000+. We provide transparent estimates before work begins.

After remediation, how do I prevent mold from returning?

Regular gutter maintenance, proper grading, ventilation, humidity control, and annual inspections are essential. We recommend seasonal maintenance for Bellevue homes.

Call (425) 800-4775 for a free mold assessment in your Bellevue home. We’ll identify any mold issues and discuss solutions keeping your family healthy and your property protected.

Get a Free Quote Today

Licensed • Bonded • Insured • Serving Bellevue & King County

We respond within 2 hours • (425) 200-1831

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