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 Renton, WA

Mold Remediation in Renton, WA | Flooding & Water Damage Specialists

Renton’s diverse landscape—from Boeing’s influence and The Landing development to older neighborhoods like Kennydale and areas near the Cedar River—creates multiple mold risk factors. Flood-prone areas near the Cedar River, heavy rainfall, and aging housing stock in some neighborhoods mean many Renton homeowners face chronic moisture and mold challenges. Prolific Design-Build and Restoration provides professional mold remediation addressing Renton-specific moisture risks.

Why Renton Homeowners Choose Prolific

Renton’s geography and climate create mold risks beyond typical Pacific Northwest moisture. Homes near the Cedar River face seasonal flooding and prolonged moisture exposure. Lower-elevation properties experience standing water and soil moisture affecting crawl spaces. Older residential areas feature vintage homes with moisture vulnerabilities. Newer construction in The Landing and surrounding developments sometimes experiences installation issues creating moisture paths.

Beyond flooding, Renton’s diverse housing stock means varied moisture challenges: aging foundations, outdated waterproofing, poor drainage systems, and ventilation deficiencies. Boeing’s industrial presence contributes dust and particulates that interact with moisture, creating additional indoor air quality concerns.

We’re licensed for professional mold remediation. We’ve addressed flood-related mold, aging-home moisture issues, and modern construction moisture problems across Renton neighborhoods.

Our Mold Remediation Process

Step 1: Comprehensive Assessment — We inspect your home for mold, conduct air quality testing, and specifically evaluate flood risk and moisture intrusion points. Renton-specific moisture sources receive special attention.

Step 2: Moisture & Flooding Risk Evaluation — We assess your flood risk and identify chronic moisture sources. This guides both remediation and prevention strategy.

Step 3: Professional Mold Removal — Following EPA standards, we safely remove mold, control spores, dispose of contaminated materials, and treat affected areas with approved fungicides.

Step 4: Comprehensive Moisture Control — For flood-prone properties, we evaluate sump pump systems, grading, and foundation waterproofing. For all homes, we address moisture sources identified during assessment.

Step 5: Documentation & Monitoring — Post-remediation testing confirms success. We discuss seasonal monitoring for flood-prone Renton properties.

Why Choose Prolific for Renton Mold Remediation

Licensed mold remediation specialists understanding Renton’s unique challenges—flooding, diverse housing stock, industrial moisture concerns. Xactimate certified for insurance documentation. Experience with flood-related mold and water damage restoration. We work with Renton homeowners and insurance companies to address moisture problems comprehensively.

Service Areas from Renton

Renton neighborhoods including The Landing, Kennydale, Cedar River area, and surrounding communities throughout South King County.

Frequently Asked Questions

What should I do if my Renton home floods?

Contact us immediately. Prompt action prevents mold colonization. We dry affected areas, assess damage, salvage items when possible, and guide insurance claims. Faster response means better outcomes.

How does Cedar River flooding affect my home’s mold risk?

Properties near the Cedar River face elevated flood risk and prolonged moisture exposure. We recommend sump pump systems, foundation waterproofing, and elevated electrical/mechanical systems. Prevention is more cost-effective than remediation.

Is mold covered by my Renton homeowner’s insurance?

Mold from sudden events (burst pipes, acute flooding) is often covered. Gradual moisture mold may not be. We help document the cause and work with your insurer on coverage questions.

How can I reduce mold risk in my Renton home?

Sump pump maintenance, gutter management, foundation grading, crawl space ventilation, and humidity control are essential. For flood-prone properties, consider elevated critical systems. We recommend annual assessments.

Protect your Renton home from mold. Call (425) 800-4775 for a free assessment. We’ll evaluate your mold risk and discuss solutions keeping your home safe and healthy.

Get a Free Quote Today

Licensed • Bonded • Insured • Serving Renton & King County

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

Get a Free Quote Today

Licensed • Bonded • Insured • Serving Renton & 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