Luxury Custom ADU & Detached
Guest House Builder
in Marin & Santa Clara Counties
From custom detached ADUs and garage conversions to independent living suites and full ground-up construction. We build beautiful, fully permitted secondary dwellings.
via Thumbtack
These accreditations and the 32 five-star Google reviews reflect our original Marin County (San Rafael) office. Our South Bay office is newer and is building its own review history and directory listings.
Three stages, one seamless ground-up build.
Every custom ADU project we execute in Marin and Santa Clara Counties moves through a disciplined contractor process, ensuring architectural integrity, transparent budgets, and zero surprises.
Zoning Feasibility & Concept Design
We evaluate your property's setbacks, assess local zoning laws, explore layout configurations, and establish a fixed-price preliminary budget for your ADU.
Engineering, Permits & Procurement
Our in-house team drafts architectural plan sets, secures municipal building permits, and coordinates Title 24 compliance before breaking ground.
Ground-Up Build & Turnkey Delivery
From foundation pouring, trenching, and framing to artisan finish carpentry and final city sign-offs, we deliver a completely independent, move-in ready home.
Every trade, permit, and custom finish, orchestrated by one master builder.
Ground-up ADU construction demands master-level coordination across structural engineering, trenching, foundation pouring, plumbing, high-voltage electrical, and artisan finishes. As licensed general contractors, we manage the entire build under one unified contract.
Detached Custom ADUs
Complete ground-up construction of fully independent backyard cottages, custom designed to match or complement your main residence's architectural style.
Garage & Attached Conversions
Transforming underutilized garages and attached spaces into beautiful, legal, fully habitable Junior ADUs (JADUs) or private guest suites.
Foundation & Trenching
Comprehensive site preparation, professional grading, new concrete foundation pouring, and structural framing engineered for seismic safety.
Separate Utility Metering & MEP
Expert trenching and connection to city sewer lines, water mains, and establishing separate electrical panels and meters for fully independent utilities.
City Planning & Permits
We handle all local zoning feasibility studies, architectural drafting, Title 24 compliance, and manage the entire city permit approval process on your behalf.
Turnkey Interior Finishes
From custom cabinetry and stone countertops in the kitchenette, to luxury flooring and tiled bathrooms, we deliver a completely finished, move-in ready home.
Realistic timelines. Zero guesswork. Built around your life.
ADU builds require meticulous phase sequencing. By finalizing site zoning, securing permits, and coordinating underground trenching prior to foundation work, we condense on-site construction to an efficient, predictable schedule.
More than just a backyard. Independent living.
A custom Accessory Dwelling Unit transforms your underutilized property into a versatile living space, perfect for family members, guests, or generating passive rental income.
Multigenerational living & flexible space
Create a comfortable, private home for aging parents, adult children, or extended family, keeping loved ones close while maintaining independent privacy.
Passive rental income generation
Maximize your property's earning potential by building a fully permitted, detached rental unit or converting an existing garage into a high-yield investment.
Significant property value appreciation
A legally permitted, architecturally cohesive ADU adds substantial square footage and significant resale value to your primary residence in the competitive Bay Area market.
Real Results, Custom ADUs
Hear directly from Marin and Santa Clara County homeowners who trusted Clear Design & Build for their custom ADU and guest house builds.
Hear What Our Clients Have to Say
"Our Entire Living Floor Feels Like a Modern Masterpiece"
An expansive kitchen and living room transformation featuring open-concept wall removal, custom millwork, and cohesive modern finishes.
"From Start to Finish, the Experience Was Flawless"
A whole-home remodel including structural changes, new flooring, lighting design, and a modernized open floor plan.
Let's Build Something Extraordinary
Ready to start your custom ADU project? Schedule a free consultation with Clear Design & Build today.
Book A Free ConsultationReal answers about primary suite remodeling, straight from the contractor.
Primary suite additions involve structural expansions, plumbing integrations, Title 24 energy standards, and multi-stage city inspections. Here is what you need to know before starting your project in Marin or Santa Clara Counties.
What are the latest California ADU laws, and how do they impact my property?
Recent California legislation has significantly relaxed zoning restrictions, allowing most single-family homeowners to build at least one detached ADU and one Junior ADU (JADU). We stay current on all Marin and Santa Clara County specific setbacks, height restrictions, and permitting requirements, handling the entire municipal approval process for you.
What is the benefit of a unified design-build contractor for an ADU vs. separate subcontractors?
Building a ground-up ADU requires orchestrating architects, concrete layers, framers, plumbers, and electricians. Hiring them separately frequently leads to finger-pointing, expensive change orders, and timeline delays. With our unified design-build approach, architectural feasibility and construction pricing happen simultaneously. You receive a fully permitted ADU built to realistic budgets with single-source accountability.
How long does a ground-up custom ADU typically take to build?
A custom detached ADU ranges from 12 to 16 weeks of active on-site construction, depending on size and site conditions. To maintain momentum, we finalize structural engineering, obtain building permits, and procure custom finishes before trenching begins, ensuring continuous on-site progress without supply chain delays.
Will building an ADU disrupt our daily life in the main house?
Because ADU construction is primarily isolated to your backyard or garage, the disruption to your main living space is minimal. We establish clear construction perimeters, manage daily site cleanups, and coordinate utility tie-ins efficiently to ensure your home remains comfortable and safe throughout the build.
How do you deliver transparent, fixed pricing without surprise change orders?
We believe true transparency starts before construction begins. By performing comprehensive site surveys, evaluating trenching routes for utilities, and locking in finish specifications during pre-construction, we provide detailed, itemized fixed-price proposals rather than unpredictable estimates.