Garage Conversion ADU — Turn Your Existing Garage Into a Permitted Living Space
A garage conversion ADU transforms your existing garage structure into a fully permitted, self-contained dwelling unit. Because the shell is already standing, conversions are typically the fastest and most affordable path to adding a livable unit on your property.
Uni Construction has designed garage conversions across Diamond Bar, West Covina, Hacienda Heights, Rosemead, and throughout the San Gabriel Valley. Our team evaluates every aspect of your existing structure to design a conversion that passes city inspection the first time.
Why Homeowners Choose Garage Conversions
Lowest cost ADU option — reusing existing walls, roof, and foundation significantly reduces construction expense
Fastest timeline — less new construction means quicker completion
No setback issues — California law does not require setbacks for conversions of existing legal structures
No replacement parking required — state law prohibits cities from requiring replacement parking when a garage is converted
Exempt from many impact fees when under 750 sq ft
What Our Evaluation Covers
Garage conversions are not as simple as adding drywall. The existing structure needs to be evaluated for residential occupancy standards. Our design process includes:
Foundation assessment: Most garage slabs are thinner than residential requirements. We determine if reinforcement or a new slab is needed.
Structural evaluation: Wall framing, roof structure, and load-bearing capacity are analyzed to confirm the structure can support residential use.
Electrical upgrade: Garages typically have minimal electrical. We design a full residential electrical layout including panel upgrades if necessary.
Plumbing design: Kitchen and bathroom plumbing are designed with the most efficient route to existing sewer and water lines.
Insulation & ventilation: Garages are uninsulated. We specify wall and ceiling insulation, and design ventilation to meet Title 24 energy standards.
Ceiling height check: Residential code requires a minimum 7’-0” ceiling height. If your garage slab is too high, we design solutions to meet this requirement.
What You Get
A complete permit-ready plan set including architectural plans, structural engineering, electrical and plumbing layouts, Title 24 energy compliance, and CALGreen documentation. We handle plan check corrections and coordinate with your city until the permit is issued.
Common Garage Conversion Layouts
A standard two-car garage (roughly 400–500 sq ft) can accommodate a studio or one-bedroom layout with a full kitchen, bathroom, and living area. Single-car garages (200–250 sq ft) work well as JADU conversions. We also design garage-plus-addition projects where the conversion is combined with a small extension to maximize square footage.
Have a garage you’re not using? Contact us for a free feasibility report to see how it can become a fully permitted ADU.
