Do You Want To Get Started On Your ADU?
The Project
This Convoy-area homeowner had an attached garage sitting mostly unused — sharing a side wall with the main home but with no interior door connecting the two. The space looked like a garage. It functioned like a garage. But with family members needing a place to stay during extended visits, the homeowner saw something different: a private living space that could be right on the property without anyone feeling on top of each other.
They brought in IL Total Design & Build to make it happen. The goal was clear — convert the roughly 425 square feet into a fully functional ADU with a proper kitchen, bathroom, sleeping area, and laundry, all permitted and done right.
The positioning of this garage made it ideal for conversion. No interior access to the main home meant the ADU would have complete privacy from day one — no awkward shared entry, no sound between units. Family members would have genuine independence.
"We couldn't believe it didn't look like a converted garage anymore. It feels like a real apartment. Our family actually wants to stay longer now."— Homeowner, Convoy · San Diego
The Challenge
Attached garage conversions in San Diego come with a specific set of constraints that detached builds don't have. The existing structure sets the rules — you work within its footprint, its ceiling height, its framing. There's no moving walls to optimize the layout. Every square foot has to be used intentionally.
At 425 square feet, fitting a full kitchen, bathroom, sleeping space, and stacked laundry while keeping the unit livable — not cramped — required careful planning at the design stage. The layout had to be efficient without feeling like a converted garage.
Constraints going in
- Fixed footprint — 425 sq ft, no expansion possible
- Existing slab, structure, and roofline dictated the layout
- New utility connections required (kitchen plumbing, electrical upgrade)
- Exterior must match main home aesthetics per city requirements
- No interior access to main home — separate entrance only
What we delivered
- Full permitted ADU with certificate of occupancy
- Complete kitchen with appliances
- Full bathroom with shower
- Dedicated sleeping area
- Stackable washer/dryer alcove
- Private exterior entrance
- Permits pulled ahead of schedule
Project Timeline
This project ran approximately 7 months from first consultation to certificate of occupancy — faster than a detached build because we were working with an existing structure, no foundation work required.
Where the $150,000 Went
One of the most useful things a contractor can do is show you where the money actually goes. Here's the approximate breakdown for this 425 sq ft attached garage conversion:
| Line Item | Notes | Approx. Cost |
|---|---|---|
| Design & engineering | Custom floor plan, structural, Title 24 | $8,000 |
| Permits & fees | Building permit, school fees, impact fees | $9,000 |
| Demolition & site prep | Garage door removal, interior demo, cleanup | $4,500 |
| Framing & structural | New exterior wall (garage door opening), interior framing | $12,000 |
| Electrical | Panel upgrade, new circuits, fixtures, outlets | $14,000 |
| Plumbing | Kitchen rough-in, bathroom, laundry connection | $16,000 |
| HVAC / mechanical | Mini-split system, ventilation | $9,000 |
| Insulation & drywall | Full insulation package, drywall, tape, texture | $10,000 |
| Flooring | LVP throughout | $6,500 |
| Kitchen | Cabinets, countertops, sink, appliances | $18,000 |
| Bathroom | Tile, vanity, toilet, shower, fixtures | $12,000 |
| Exterior work | New wall, siding, windows, entry door, paint | $14,000 |
| Miscellaneous & contingency | Hardware, finish details, unexpected items | $7,000 |
| Total | Fully permitted, move-in ready | $150,000 |
Costs are approximate and reflect this specific project. Your project will vary based on existing conditions, finish selections, and site-specific requirements. Get a free estimate for your property →
Design & Permitting
Rummy Dechner led the design, working within the existing structure to produce a layout that maximized the space without compromising livability. The floor plan tucked the bathroom and laundry along one wall, opened the kitchen to a small living/dining area, and positioned the sleeping space to take advantage of natural light from the existing window openings.
One of the goals from the start was that this shouldn't look like a converted garage when it was done. The exterior — new wall infill where the garage door was, updated siding, windows, and entrance treatment — presents as a cohesive unit rather than an afterthought. Inside, finish selections were residential throughout.
The city permitting process moved faster than expected. A well-prepared, complete permit application is the single biggest driver of permit speed. This submission came back approved with no correction rounds.
Garage Conversion vs. Detached ADU — Which Is Right for You?
The question we get most often from Convoy and mid-city San Diego homeowners: is a garage conversion or a new detached ADU the better move? The honest answer depends entirely on your lot, your goals, and your budget.
| Factor | Garage Conversion | Detached ADU |
|---|---|---|
| Typical cost | $100K–$180K | $200K–$400K+ |
| Timeline | 6–9 months | 10–14 months |
| Size potential | Limited by existing garage footprint | Up to 1,200 sq ft (per lot allowance) |
| Design flexibility | Work within existing structure | Fully custom from ground up |
| Rental income potential | $1,500–$2,500/month (typical range) | $2,500–$4,500+/month |
| Foundation work | Existing slab — no new foundation | Full foundation required |
| Parking loss | Yes — no replacement required by law | No parking lost |
| Best for | Lower budget, faster timeline, existing structure | Maximum value, larger space, higher rental income |
Project Gallery
Floor Plan
Exterior
During Construction
Completed Interior
Garage Conversion ADU — Frequently Asked Questions
Can any garage be converted to an ADU in San Diego?
Most attached and detached garages in San Diego can be converted to an ADU, but it depends on your specific zoning, lot size, and setback requirements. The garage must meet minimum ceiling height requirements (typically 7 ft finished height) and the structure must be able to support insulation, waterproofing, and the plumbing and electrical needed for a habitable unit.
A quick property assessment with us will confirm whether your garage qualifies and what the conversion would require.
Do I lose my parking if I convert my garage to an ADU?
California state law prohibits cities from requiring replacement parking when a garage is converted to an ADU. You do not need to provide a new covered parking space. However, if maintaining parking matters to you, options include a carport addition or converting only part of the garage if it's large enough to split.
This Convoy project had no parking replacement requirement. The homeowners simply lost the garage parking — which they weren't using anyway.
How long does a garage conversion ADU take in San Diego?
A garage conversion ADU typically takes 6–9 months from first consultation to certificate of occupancy. That breaks down as design and drawings (6–10 weeks), city permitting (60–90 days), and construction (2–3 months). This project took approximately 7 months total.
Garage conversions are significantly faster than detached ADU builds (10–12 months) because no foundation work is required — you're working within an existing structure.
How much does a garage conversion ADU cost in San Diego?
In 2025–2026, a permitted garage conversion ADU in San Diego typically costs $100,000–$180,000 depending on size, finish level, and site conditions. This Convoy project came in at $150,000 for a 425 sq ft unit with a full kitchen, bathroom, sleeping area, and stackable laundry.
The main cost drivers are plumbing rough-in (if new), electrical panel upgrades, insulation, drywall, kitchen and bathroom finishes, and exterior work to infill the garage door opening.
Do I need a permit to convert my garage to an ADU?
Yes — a permit is required for any garage-to-ADU conversion in San Diego. The city reviews plans for structural compliance, energy code (Title 24), fire safety, plumbing, and electrical. Permit fees typically run $5,000–$15,000 for a garage conversion ADU in San Diego.
Unpermitted conversions create serious problems when you sell or refinance, and cannot be legally rented. Every garage conversion we build is fully permitted with a certificate of occupancy.
What's the difference between a garage conversion and a detached ADU?
A garage conversion works within an existing structure — lower cost ($100K–$180K), faster timeline (6–9 months), but limited square footage and design flexibility constrained by the existing garage footprint.
A detached ADU is built from the ground up — more design freedom, larger potential size, higher rental income potential, but significantly higher cost ($200K–$400K+) and longer timeline (10–14 months). The right choice depends on your lot, budget, and goals. We can walk through both options at your property assessment.
Have a Garage You're Not Using?
A permitted garage conversion is typically the lowest-cost path to adding livable space on your property. We handle design, permits, and construction — one team, start to finish.
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