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.

Roofing Contractor Covington WA

Prolific Design-Build and Restoration provides roofing replacement, repair, and storm damage services throughout Covington, WA. Covington’s residential neighborhoods — including areas along SE 256th, the Covington Community area, and properties bordering Soos Creek — face the same Pacific Northwest moisture challenges as the rest of King County, but with more tree coverage and larger lots that make moss growth, debris buildup, and drainage management particularly important.

Roofing Services in Covington, WA

Roof Replacement: Complete tear-off and new installation for Covington’s single-family homes, including evaluation of decking condition, proper ventilation setup, and installation of ice-and-water shield in all valleys and eaves. We use 30-year and 50-year architectural shingles and can source metal roofing options when a premium long-term solution is the right fit.

Roof Repair: Leak diagnosis and targeted repair for missing shingles, failed valley flashing, pipe boot cracks, and chimney counter-flashing separation. We find the actual source of the leak — not just the spot where water is showing up inside.

Storm Damage Response: Covington sits in a region that sees real wind events and regular heavy rain. We respond to storm calls, document damage in detail for insurance claims, and work with your adjuster to make sure covered repairs get approved.

Moss Removal & Treatment: Covington’s mature trees and shaded lots mean moss is almost guaranteed without periodic treatment. We clear existing growth, protect your shingles, and apply zinc or copper strip systems to slow regrowth long-term.

Gutter Replacement & Repair: Proper drainage starts at the gutter. We replace failed gutter sections, install leaf guards, and make sure water is moving away from your foundation — not pooling at the fascia and rotting your decking.

What Makes Prolific Different in Covington

Covington is unincorporated King County — permits and inspections go through King County DPER, and we know that process well. We pull permits when required, schedule inspections, and make sure your new roof is on record as a code-compliant installation. That matters for your home’s value, your insurance coverage, and your peace of mind.

We’re a small team — you get the same people from estimate through final walkthrough. No handoff to a subcontracted crew. No salesperson who disappears once the contract is signed. We answer our phones, show up when we say we will, and stand behind our work.

Roofing Process — What to Expect

Inspection & Estimate: We inspect your roof, check the attic for ventilation and moisture, and give you a written estimate with itemized labor and materials. Free, no strings attached.

Scheduling: We fit the work to your schedule. Most Covington replacements take one to two days. We confirm the date, order materials, and protect your driveway and landscaping before work begins.

Installation & Cleanup: Full tear-off, new underlayment, installation, and a magnetic nail sweep at the end of every day. We don’t leave a messy job site overnight.

Final Walkthrough: We review the completed work with you, deliver warranty documentation, and make sure every detail meets your expectations before we call it done.

Frequently Asked Questions — Covington Roofing

Do you pull permits for Covington roofing work?
Yes. Full replacements require a King County building permit. We handle the application and inspection scheduling — you don’t have to deal with the county paperwork.

How much does a roof replacement cost in Covington?
Most single-family roof replacements in Covington range from $8,000 to $18,000 depending on roof size, pitch, and material choice. We provide a detailed written estimate so there are no surprises.

Can you work with my insurance company on a storm claim?
Absolutely. We document damage with detailed photos, prepare a scope-of-loss estimate in the format adjusters expect, and communicate with your insurance company directly. Most of our storm repair clients in Covington pay only their deductible.

Serving Covington, Maple Valley, Kent, and Southeast King County. Call (425) 800-4775 or get a free Covington roof estimate — we typically schedule within 2–4 business days.

Also Serving Nearby Cities

Prolific Design-Build and Restoration provides the same professional service across King County.

View all Roofing Services in King County

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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