Additions & ADUs.
Permitted additions, ADUs, accessory dwelling units.
King County loves ADUs. We handle design through final inspection — permit application, foundation, framing, MEP, finish.
Start your additions & adus intake.
To start a Prolific additions & adus estimate, send the basics below and you'll get an AI-priced number in about 60 seconds — no salesperson and no obligation.
How additions & adus works with Prolific.
Every Prolific additions & adus project in King County follows the same path: a 60-second AI estimate, a photo upload that tightens it to ±8%, a 30-minute walkthrough that locks the final price, and then we build to that number.
- Basic intake — 60 seconds
An AI estimate priced from real completed King County jobs. ±15%, no salesperson, no phone tag.
- Photo upload — 2 minutes
Send photos and the number tightens to ±8%. We arrive ready instead of guessing on site.
- Walkthrough — 30 minutes
Every property gets walked. The walkthrough number is the number — that is what you sign.
- We build
Written scope, Prolific crew, and the price you locked at the walkthrough. No change-order theater.
What you get. Always.
Every Prolific additions & adus project includes design + permit-ready drawings, site survey + foundation engineering, mep coordination — written into the scope before work starts, not sold as an upgrade later.
Recent additions & adus work.
Additions & ADUs in 14 King County cities.
Prolific provides additions & adus in all 14 King County cities we serve — Issaquah, Bellevue, Renton, Maple Valley, Covington, Black Diamond, Enumclaw, Sammamish, Newcastle, Snoqualmie, North Bend, Mercer Island, Kirkland, Federal Way — dispatched from our Issaquah headquarters with the same crew, scope discipline, and warranty in every one.
Additions & ADUs — straight answers.
Is additions & adus covered in King County?+
Yes. Prolific serves all 14 King County cities for additions & adus — Issaquah, Bellevue, Renton, Maple Valley, Covington, Black Diamond, Enumclaw, Sammamish, Newcastle, Snoqualmie, North Bend, Mercer Island, Kirkland, Federal Way.
What does Prolific include in this scope?+
Design + permit-ready drawings · Site survey + foundation engineering · MEP coordination · Inspection scheduling · Final occupancy certificate
Are you licensed and certified?+
WA GC #PROLISN776L6. IICRC S500/S520/S540 certified. Xactimate certified. Founded 2021.
Something else on your mind? Call (425) 800-4775 — 24/7, a person answers.