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Garage Conversion ADU Contractor in the Bay Area
Hamilton Exteriors builds the garage conversion ADU from plan to final inspection. The job includes structural work, utilities, and permits. Serving the Bay Area and Northern California.
500+ projects
Since 2018
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Converting an existing garage into an ADU starts with the shell. We check the slab, finished ceiling height, framing, fire separation, access, and utility routes before drawing the floor plan. Those findings show what the space needs for permit approval and construction.
A garage conversion is more than flooring and drywall. It can require slab moisture work, insulation, new windows, fire separation, electrical upgrades, plumbing, ventilation, and permanent heating. We coordinate those items in the permit set before construction begins.
Field work must follow the approved garage conversion plans, especially where the slab, former door opening, utilities, and fire separation meet the existing shell. When an uncovered condition changes one of those details, we document it and coordinate the needed revision before covering the work.
How We Convert a Garage Into an ADU
Each project moves from an existing-condition review to permitted construction.
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Assess the Existing Garage
We measure the slab, ceiling, framing, openings, access, and utility routes. This review identifies repairs and design limits before the permit set begins.
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Design and Permit the ADU
We coordinate the floor plan, structure, energy documents, fire separation, and building systems. The completed package goes to the local agency for review.
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Build Through Final Inspection
Our team follows the approved plans through structural work, utilities, insulation, finishes, required inspections, and project closeout.
Garage Conversion Feasibility Check
| Item | What We Review | Why It Matters |
|---|---|---|
| Slab | Condition, level, and moisture control | Supports durable finished flooring |
| Ceiling | Existing and finished height | Must support legal living space |
| Utilities | Electrical, water, sewer, and HVAC paths | Drives layout and construction scope |
| Fire separation | Shared walls, doors, and openings | Protects attached living areas |
| Light and access | Windows, entry, and emergency egress | Creates safe, usable rooms |
From Garage to Permitted ADU
The plan starts with measured existing conditions. We document the slab, framing, roof, openings, and utility locations. The design then sets the living layout, windows, entry, kitchen, bathroom, and mechanical systems. Engineering and energy documents support the permit package. Construction follows the approved set through final inspection.
Plan Structure and Utilities Together
A good floor plan must work with the building. Plumbing should follow a practical route to the sewer. Electrical capacity must support cooking, water heating, heating, cooling, and normal outlets. New openings must fit the existing load path. Planning these systems together reduces field changes and keeps the usable area efficient.
Make the Garage Feel Like a Home
The former garage door opening needs careful framing, weather protection, windows, and exterior finishes. Inside, storage, daylight, ventilation, and furniture clearances matter more than decorative details. We design the conversion around daily use so the finished space feels intentional from the street and from inside.
Garage Conversion Financing Options
Garage conversion costs can include design, engineering, permit fees, utility work, and construction. Financing is available with approved credit for homeowners who prefer scheduled payments instead of one upfront project expense. During your consultation, we explain available terms, eligible project costs, and payment timing.
Ask about garage conversion financing during your consultation.
Call Now (650) 977-3351 Garage Conversion Reviews
Homeowner feedback from ADU and remodeling projects.
Yaku Escobar
via Google
We worked with Hamilton Exteriors to build a small ADU in our backyard. from the beginning the process felt organized and clear. Alex Lee was very responsive and always kept us in the loop, especially during planning and inspections. The crew was consistent and respectful of the space which we appreciated since we were living there during the build. overall everything moved pretty smoothly and the final result looks exactly like what we had in mind. really happy with how it turned out.
Rafa Simons
via Google
My family hired Hamilton after seeing the neigbours new ADU, the whole team were super organized and tecnological and also very patient to undestand my needs before starting the construction. But what i like the best is that they are really preocupated with the final result and they kept us well inform with details and everything. Definitely recomend them.
Kevin L
via Google
We hired them for a bigger renovation. Alex was very responsive, which I appreciated. We changed a couple requirements during the job and they worked with us on it without making it complicated. Overall, everything went pretty smooth and their quality of work is solid. I recommend them highly!
Jacob Rothwell
via Google
Alex Li helped me with my basement remodeling, they were super efficient, and the work came out better than I could’ve ever imagined! Thank me later!
Frequently Asked Questions
Didn't find the answer to your question? Call Now (650) 977-3351
Can you convert both attached and detached garages into ADUs?
Yes. Both can work. An attached garage needs careful fire separation from the main home. A detached garage can require longer utility runs. We review the structure, setbacks, access, and service connections before recommending a plan.
What existing conditions can change the garage conversion scope?
Common factors include slab moisture, low ceilings, weak framing, limited electrical capacity, and distance from the sewer connection. An early site review identifies these items before permit drawings and pricing are complete.
Do garage conversion ADUs need replacement parking?
Parking rules depend on the property and current local review. We confirm whether replacement parking applies before permit submission.
Can part of the garage remain for parking or storage?
Sometimes. The remaining area must still work with parking, fire separation, access, and utility requirements. We measure the garage and test partial-conversion layouts before recommending this approach.
How long does garage conversion construction take?
Construction often takes six to ten weeks after permits and material ordering. Structural repairs, utility upgrades, custom windows, and inspection timing can extend the schedule. We set the project sequence before work starts.
What happens to the existing garage door opening?
The approved design usually replaces the garage door with a framed, insulated, and weatherproof wall. Windows, exterior cladding, and interior finishes make the opening part of the new living space.
Get Your Garage Conversion ADU Quote
Tell us about your project. We usually call within 3–5 minutes.
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