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.

🏡

Detached ADU (DADU)

A standalone dwelling in your backyard. Most flexible for rental or multigenerational living. Requires setback compliance and separate utility connections.

🏗

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.

🏠

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 Bellevue WA

Prolific Design-Build and Restoration provides roofing services throughout Bellevue, WA — from Bellevue’s Eastside neighborhoods like Crossroads and Somerset to the larger estates in Medina-adjacent areas and the newer construction in neighborhoods like Factoria and Coal Creek. Bellevue’s urban canopy and wet winters create consistent roofing challenges: moss buildup on shaded north-facing slopes, gutter overload during heavy rain events, and premature shingle aging on roofs that go years without inspection.

Roofing Services in Bellevue, WA

Roof Replacement: Full tear-off and installation on Bellevue residential and commercial properties. We evaluate decking condition, upgrade ventilation where needed, and install with the precision required to maintain manufacturer warranty coverage. Material options include architectural asphalt shingles, metal roofing panels, and designer shingles in a range of profiles and colors.

Storm & Wind Damage Repair: Bellevue’s position between Lake Washington and the Cascade foothills means real wind events, particularly in fall and winter. We photograph and document damage in detail, communicate with your insurer, and repair to code with matching materials wherever possible.

Leak Repair & Diagnostics: Leak sources in Bellevue’s older neighborhoods are frequently at valleys, chimneys, skylights, and step flashing — not where the water appears inside. We trace the source and fix it correctly, not just apply a temporary sealant.

Moss Removal & Prevention: Bellevue’s mature residential tree cover creates shade conditions that grow moss aggressively. We remove existing moss, treat the shingles, and install zinc strip systems along the ridge to inhibit regrowth over time.

Roof Inspections: Pre-purchase inspections, annual maintenance checks, and post-storm evaluations with written reports and photo documentation. Bellevue’s competitive real estate market makes roof condition a real factor in negotiations — we give buyers and sellers a clear picture.

Roofing a Home in Bellevue — What We Know

Bellevue has a mix of home ages and construction types that requires adaptable roofing expertise. The original 1960s and 1970s ranchers in areas like Lake Hills often have original skip-sheathing decking that needs evaluation before re-roofing. The high-end custom construction in West Bellevue may require premium materials and specific manufacturer certifications to maintain warranty coverage. The newer townhomes and condos in the Bel-Red corridor have low-slope sections that require different materials and detailing than standard pitched roofs.

We’ve worked across all of these and we approach each project specifically — not with a one-size formula. Prolific is licensed and bonded in Washington State, carries full liability and workers’ comp coverage, and we pull City of Bellevue permits on all projects that require them.

Frequently Asked Questions — Roofing in Bellevue

Does Bellevue require a permit for roof replacement?
Yes. The City of Bellevue requires a building permit for full roof replacements. We handle permit applications and coordinate with the city inspection process so you don’t have to.

What roofing materials are most popular in Bellevue?
Bellevue homeowners typically choose 30-year or 50-year architectural shingles for standard homes. Higher-end properties in West Bellevue and Medina frequently opt for metal standing seam or premium designer shingles. We carry samples and can show you local examples of any option.

How long does a Bellevue roof replacement take?
Most single-family homes complete in one to two days. Larger homes, complex roof lines, or projects requiring significant decking repair may take three to four days. We give you a realistic schedule upfront.

Can you match my existing shingles for a partial repair?
We make every effort to match, but older shingle lines are often discontinued. We’ll show you the closest match available and give you an honest assessment of how visible the difference will be before you decide.

Serving all Bellevue neighborhoods and surrounding Eastside communities. Call (425) 800-4775 or request a free Bellevue roof estimate. We schedule most Bellevue inspections within 2–3 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
Back to Home

Prolific Design-Build & Restoration — Federal Way, WA

📋 Get a Free Estimate