ADU & DADU Construction in Kirkland & Bellevue, WA
Add rental income, multigenerational living, or a home office to your property. Urban Builder LLC specializes in permitted ADU and DADU construction throughout King County.
Accessory Dwelling Unit Experts in the Seattle Eastside
An ADU (Attached/Detached Accessory Dwelling Unit) or DADU (Detached ADU) is one of the smartest investments a Kirkland or Bellevue homeowner can make. With Washington state ADU-friendly legislation and high rental demand, a well-built ADU can generate $2,000–$3,500/month in rental income.
Urban Builder LLC handles everything from permit drawings through final inspection — so you can focus on the financial upside while we manage the construction.
- Detached ADU / Backyard cottage construction
- Attached ADU (converted garage, addition)
- Basement ADU conversions
- Junior ADU (JADU) — within primary home
- Full kitchen, bath & living space
- Separate utility metering available
ADU Investment Snapshot
✔ Typical ADU cost: $150,000–$350,000
✔ Average King County rental income: $2,000–$3,500/mo
✔ Typical ROI period: 5–10 years
✔ Increases property value 20–35%
✔ Licensed contractor (Lic# URBANBL753LF)
ADU Construction Process
We make ADU construction simple, transparent, and stress-free
Free Site Feasibility Review
We evaluate your lot size, setbacks, zoning, utility access, and HOA rules to confirm ADU feasibility and maximum allowable size before you spend a dollar.
Design & Floor Plan
Our design team creates efficient floor plans that maximize livable space within city setback requirements — studio, 1BR, or 2BR layouts available.
City Permits & Engineering
We prepare and submit all permit applications to Kirkland, Bellevue, Redmond or your city — handling all back-and-forth with the building department.
Site Prep & Foundation
Site clearing, utility extensions, foundation preparation, and slab or crawlspace installation — all to city code and engineered specifications.
Framing, Systems & Finishes
Full construction including framing, roofing, siding, windows, HVAC, plumbing, electrical, insulation, drywall, flooring, and kitchen/bath finishes.
Final Inspection & CO
We obtain your Certificate of Occupancy and walk you through everything. Your ADU is ready to rent or move family in.
ADU Types We Build
Detached Backyard Cottage
A fully independent structure in your backyard — ideal for rental income, guest quarters, or multigenerational living.
Garage Conversion ADU
Convert your detached or attached garage into a full living space — one of the most cost-effective ADU options available.
Basement ADU
Transform an underused basement into a legal, permitted apartment with separate entrance, kitchen, and bathroom.
Above-Garage ADU
Add a second story above your detached garage to create a private living unit with minimal footprint impact.
Frequently Asked Questions
Ready to Add an ADU to Your Property?
Find out if your lot qualifies and get a free estimate. Serving Kirkland, Bellevue, Redmond, Bothell, Woodinville & all of King County.