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.

How to Get a Building Permit in Kirkland, WA

Target keywords: Kirkland building permit | deck permit Kirkland WA | Kirkland planning building department | permit cost Kirkland


Kirkland is a mid-size city on the east shore of Lake Washington. Its building department handles permits for the original Kirkland area as well as the Finn Hill and Juanita neighborhoods annexed from King County. Here’s what homeowners need to know.

Does My Project Need a Permit in Kirkland?

Decks Attached decks require a permit. Detached platforms under 200 SF and less than 30 inches above grade are typically exempt.

Fences Fences up to 6 feet in rear and side yards are generally exempt. Fences near the waterfront (Kirkland’s shoreline overlay) have additional height and visual-clearance requirements.

ADUs Kirkland allows ADUs under its zoning code. Building permit required. The city has been updating its ADU rules to align with state law — confirm current setbacks and size limits.

Interior Remodels Standard code applies for structural, electrical, plumbing, and HVAC work.

Kirkland Permitting Department

City of Kirkland Planning & Building Department – Website: kirklandwa.gov/building – Permit portal: Available through the city’s online system – Phone: (425) 587-3600 – Address: 123 5th Ave, Kirkland, WA 98033

Permit Fees in Kirkland

ProjectEstimated Fee
Deck (200–400 SF)$450–$850
Fence (if required)$175–$350
ADU$2,200–$5,000+
Kitchen remodel (structural/mechanical)$650–$1,500
Room addition$1,300–$3,200

How Long Does Permitting Take in Kirkland?

  • Simple projects: 2–4 weeks
  • Standard residential: 6–12 weeks
  • Lakefront / critical area projects: Add 4–8 weeks for shoreline review

What Kirkland Inspectors Check

Standard structural and code inspections. Projects near Lake Washington or within the shoreline management overlay area require additional review. Kirkland takes its tree canopy regulations seriously — significant tree removal in conjunction with construction may require a separate tree removal permit.

Let Prolific Handle the Permits

We handle permitting for Kirkland projects including shoreline setback coordination. Get an estimate →


Schema: Kirkland Permitting Guide

{
  "@context": "https://schema.org",
  "@type": "FAQPage",
  "mainEntity": [
    {
      "@type": "Question",
      "name": "How long does it take to get a permit in Kirkland?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Standard residential permits in Kirkland take 6–12 weeks. Projects near Lake Washington or in the shoreline overlay area can take 4–8 weeks longer due to additional shoreline review."
      }
    },
    {
      "@type": "Question",
      "name": "Do I need a permit for a deck in Kirkland?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Decks attached to your home require a permit in Kirkland. Detached platforms under 200 SF and less than 30 inches above grade are typically exempt."
      }
    }
  ]
}


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