Los Angeles · Garage Conversion
How much does a garage-to-ADU conversion cost in Los Angeles in 2026?
Published 2026-05-25 · Reviewed by Dror Gigi, Co-Founder
Short answer
A standard two-car garage conversion to an ADU in Los Angeles costs $95,000 to $165,000 in 2026, for a finished 400 to 500 sqft living space. This is roughly 35 to 45 percent less than building a new detached ADU of the same size because the foundation, walls, and roof already exist.
A garage conversion uses the existing concrete slab, perimeter walls, and roof structure, which removes about $50,000 to $80,000 of the cost of a new detached ADU. What you pay for instead is the work of bringing an unconditioned, unfinished structure up to habitable building code: insulation, weatherization, full plumbing, electrical service, HVAC, windows, and a livable interior. California's ADU laws (AB 68, SB 9, plus the 2024 LA-specific implementations) make garage conversions a streamlined permit path in most LA neighborhoods.
Cost breakdown for a 450 sqft garage-to-ADU conversion, LA 2026
| Component | Low end | Mid | High end |
|---|---|---|---|
| Permits + plan check (LADBS) | $3,500 | $6,500 | $9,500 |
| Structural reinforcement (header beam, shear wall) | $4,500 | $8,500 | $15,000 |
| Insulation + weatherization (walls, roof, slab) | $5,500 | $9,500 | $14,000 |
| New windows + entry door | $3,500 | $6,500 | $11,000 |
| Plumbing rough + fixtures | $11,000 | $18,000 | $28,000 |
| Electrical rough + service upgrade | $8,500 | $13,000 | $22,000 |
| HVAC (heat pump mini-split or central) | $5,500 | $8,500 | $13,500 |
| Drywall + interior finishes | $11,000 | $18,000 | $28,000 |
| Kitchenette + bath | $14,000 | $22,000 | $38,000 |
| Flooring, paint, trim | $5,500 | $9,500 | $15,000 |
| Utility connections (separate meter optional) | $3,500 | $8,500 | $15,000 |
| Contractor overhead and profit | $13,500 | $22,000 | $35,000 |
| Total | $89,500 | $150,500 | $244,000 |
What most homeowners under-budget
Structural reinforcement of the garage opening
The big garage door opening is a structural gap in the shear wall. Converting that opening into a wall with a window or door requires a structural engineer-designed header beam, a new shear wall section, and a foundation tie-down. Budget $4,500 to $15,000 depending on the span and seismic zone.
Slab insulation and moisture barrier
A garage slab is typically uninsulated and lacks a continuous moisture barrier. To meet California Title 24 for a habitable space, you either insulate above the slab (raised subfloor, $4 to $9 per sqft) or accept the energy code workaround via above-code wall and roof insulation. The raised subfloor approach is more durable and typically what permit reviewers prefer.
Electrical service capacity
Most LA homes with attached garages have 100-amp or 125-amp service. An ADU with a heat pump, induction or gas range, water heater, washer-dryer, and EV charger needs at minimum 200-amp service. Panel upgrade runs $4,500 to $8,500 in 2026 LA.
LA-specific code notes for garage conversions
- Setbacks: an existing legal garage in a non-conforming setback (within 5 ft of a side property line, for example) can typically be converted in place under AB 68 without needing variance
- Ceiling height: minimum 7 ft 0 in for habitable space; many older LA garages have 7 ft 6 in to 8 ft 0 in which is sufficient
- Egress windows: every bedroom needs a window with a 5.7 sqft clear opening
- Fire separation: 1-hour fire-rated wall between the ADU and the primary house if attached, and 5-foot setback or 1-hour exterior wall if detached and within 5 ft of the house