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 Issaquah WA

Prolific Design-Build and Restoration serves homeowners and property owners throughout Issaquah, WA with professional roofing replacement, repair, and storm damage services. Issaquah’s location at the foot of the Cascade foothills brings heavier rainfall than Seattle, real snow accumulation in some winters, and the kind of sustained moisture and leaf debris that puts roofs through more stress than most homeowners realize. We’ve worked on roofs in the Issaquah Highlands, Squak Mountain area, downtown Issaquah neighborhoods, and out toward Cougar Mountain — and we know what local roofs deal with season to season.

Roofing Services in Issaquah, WA

Roof Replacement: Full tear-off and new installation with underlayment, ice-and-water shield, and ventilation upgrades as needed. Material options include 30-year and 50-year architectural shingles, metal roofing, and premium designer shingle lines. We select materials appropriate for Issaquah’s precipitation and occasional snow load — not just what’s cheapest to install.

Storm Damage Repair: Issaquah gets meaningful wind and rain events off the Cascades. We respond quickly, inspect thoroughly, and document damage in the detail that insurance adjusters need to approve claims. Many Issaquah storm repairs are fully covered — minus the deductible.

Roof Repair: Leaks are almost never where they look like they originate. We trace moisture back to the actual entry point — often at valley intersections, around skylights, or at chimney flashing — and repair it correctly rather than applying a bandage.

Moss & Algae Control: Issaquah’s tree coverage and humidity are ideal conditions for moss. Unchecked, moss roots lift shingle granules and dramatically shorten roof life. We treat, remove, and install prevention systems that work between visits.

Inspections: Pre-purchase inspections are especially valuable in Issaquah’s competitive real estate market. We provide written reports with photos and a clear assessment of remaining roof life and recommended repairs — useful for negotiations and insurance documentation.

Roofing in the Issaquah Highlands & Surrounding Areas

The Issaquah Highlands represents one of Issaquah’s largest residential developments — thousands of homes, many with HOA requirements around material choices and color selection. We’re familiar with Highlands HOA roofing guidelines and can help you select materials that meet community standards while getting you the best value for your investment.

Older homes in downtown Issaquah and along the highway corridor often have original decking that needs evaluation before re-roofing — we assess it honestly and give you options if repairs or upgrades are needed before new shingles go on.

We pull City of Issaquah permits for all work that requires them, carry full liability and workers’ comp insurance in Washington State, and are licensed through the WA Dept. of Labor & Industries.

Frequently Asked Questions — Roofing in Issaquah

Does snow load affect roofing choices in Issaquah?
Issaquah can receive meaningful snowfall — particularly in the Highlands and on Squak Mountain. We factor snow load into material and structural recommendations. Metal roofing is especially well-suited to Issaquah’s higher elevation zones.

My Issaquah Highlands HOA has roofing restrictions — can you work within them?
Yes. We review HOA guidelines before finalizing material selections and can provide documentation of approved products for your HOA submission. Most major shingle manufacturers have lines approved for common HOA requirements.

How quickly can you respond to storm damage in Issaquah?
We prioritize storm response calls and typically inspect within 24–48 hours for active leaks or visible storm damage. We can apply temporary protection (tarping) while awaiting insurance adjuster visits when needed.

What does a roof replacement cost in Issaquah?
Most residential replacements in Issaquah range from $9,000–$20,000 depending on roof size, pitch, complexity, and material choice. Issaquah Highlands homes tend toward the mid-to-upper end of that range given their square footage. We provide a free detailed estimate — no ranges, no guessing.

Serving Issaquah, Sammamish, North Bend, and the I-90 corridor. Call (425) 800-4775 or schedule your free Issaquah roof inspection.

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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