An Accessory Dwelling Unit should never look like an afterthought. We design and build detached luxury suites and garage conversions that mirror the architectural language of your main home — perfect for multi-generational living, guest quarters, or high-yield estate rentals. Every ADU we build is finished to the same material standard as the primary residence.
California's ADU laws have created extraordinary investment opportunities for Marin County homeowners — but navigating the permit process, SB 9 compliance, utility connections, and design review requirements requires local expertise. Our PlanPass.ai permit intelligence platform has accelerated ADU permit approvals across all Marin County jurisdictions, and our team has completed ADU projects on lots ranging from standard urban parcels to complex hillside sites with septic system requirements.
ConstruBay (CSLB #1106798) is based in Mill Valley and has executed ADU and garage conversion projects across Marin, Sonoma, and Napa Counties.
What Is Included
The Marin Advantage
ADU permitting in Marin County is governed by state ADU law (AB 68, SB 9, AB 2221) as well as local ordinances from each of Marin's 11 cities and unincorporated county areas. Our PlanPass.ai platform maintains current ADU compliance matrices for every Marin County jurisdiction — including Tiburon, Mill Valley, Sausalito, San Rafael, Novato, Ross, Belvedere, San Anselmo, Fairfax, Corte Madera, and Larkspur. We pre-screen every ADU application for setback, height, coverage, and owner-occupancy requirements before investing in construction drawings, preventing the costly redesigns that occur when projects hit regulatory obstacles mid-design. Our team has also completed ADU projects in Sonoma County jurisdictions including the City of Sonoma, Petaluma, and unincorporated Sonoma County.
Our Process
Curation & Design
We begin with an in-depth discovery session at your property, translating your vision into a fixed-scope brief with transparent pricing.
Artful Execution
Our licensed craftsmen execute with precision under direct site supervision — every material sourced, every detail approved by you before installation.
The Final Reveal
A thorough walkthrough with your project lead ensures every element meets our standard before you take possession of your transformed space.
Investment Range
$175,000 – $450,000+
Typical Project Range
All projects are delivered under a fixed-scope contract — the number you approve is the number you pay.
Frequently Asked Questions
Begin Your Project
Begin Your ADU Project
Fixed-scope contract. No surprises. Schedule a private consultation with Paulo.