Garage conversion ($80k to $150k)
$80k–$150k
- - Convert existing 400-600 sqft garage
- - Insulation, drywall, flooring, kitchenette, bathroom
- - Reuse existing slab and framing
- - Permit, electrical upgrade, gas line if needed
Renology cost index
ADU Construction Cost Index 2026
Backyard studios, garage conversions, and income-producing guest suites.
Planning range
$80k–$400k
Updated 2026-04-18. Use as a benchmark before comparing itemized bids.
Quick answer
In 2026, adu construction projects tracked by Renology typically plan around $80k–$400k. The final number depends on local labor, site conditions, material tier, permits, demolition, access, and finish level.
Category
Structural & Envelope
Local guides
7
Materials tracked
5
Timeline
6 to 14 months
Budget tiers
ADU Construction budget levels
Use tiers to understand what kind of scope each price band usually implies before comparing local bids.
Detached ADU ($180k to $300k)
$180k–$300k
- - New 600-1,000 sqft detached unit
- - Full kitchen, 1 bedroom, 1 bath, laundry
- - Stem-wall foundation, framed construction
- - Utilities run from main house
Premium or 2-bedroom detached ($320k to $550k+)
$320k–$550k
- - 1,000-1,200 sqft (CA max)
- - 2 bedrooms, 2 baths, full kitchen, designer finishes
- - Separate utility meters, dedicated parking
- - Architectural design, premium millwork and appliances
State view
ADU Construction ranges by state
Aggregated from published city/service guides in each state.
Local guide index
City-level adu construction ranges
Open a local guide when city labor, permits, climate, or housing stock materially affect the project.
San Francisco, California
ADU Construction Cost in San Francisco (2026)
$235,000-$415,000
Local range with city-specific planning context.
Culver City, California
ADU Construction Cost in Culver City (2026)
$215,000-$385,000
Local range with city-specific planning context.
Long Beach, California
ADU Construction Cost in Long Beach (2026)
$215,000-$385,000
Local range with city-specific planning context.
Los Angeles, California
ADU Construction Cost in Los Angeles (2026)
$215,000-$385,000
Local range with city-specific planning context.
La Jolla, California
ADU Construction Cost in La Jolla (2026)
$200,000-$350,000
Local range with city-specific planning context.
San Diego, California
ADU Construction Cost in San Diego (2026)
$200,000-$350,000
Local range with city-specific planning context.
Seattle, Washington
ADU Construction Cost in Seattle (2026)
$180,000-$320,000
Local range with city-specific planning context.
Material signals
Materials that move the budget
Material pricing is not the whole bid, but it often explains why two scopes with the same project name price differently.
Both
Garage conversion (sqft cost)
$200-$320
Cheapest ADU path
Both
Detached stick-built ADU
$300-$500
Most flexibility
Both
Prefab modular ADU
$280-$450
Faster build time
SoCal
Container-based ADU
$220-$380
Modern aesthetic
Both
Site work and utilities
$15,000-$50,000
Trenching, sewer hookup
Methodology
How this cost index is built
This page combines the Renology service guide for adu construction, local city/service guides, material notes, budget tiers, and editorial review. It is designed for early planning and answer extraction, not as a contractor quote.
Compare this page with the full Renology Cost Index and the full ADU Construction guide before requesting bids.
See the Renology Methodology for how sources are reviewed, how ranges are normalized, and where the limits of planning data begin.
Answered for search
ADU Construction cost FAQ
Short answers for homeowners and AI answer systems.
How much does adu construction cost in 2026?
Renology's 2026 planning range for adu construction is $80k–$400k. Final bids depend on scope, existing conditions, materials, permits, access, and local labor.
What changes the price of adu construction most?
The largest pricing swings usually come from demolition, prep work, structural or utility changes, material tier, finish level, waterproofing or weather exposure, permit requirements, and contractor availability.
Are these numbers contractor quotes?
No. The cost index is a planning benchmark, not a fixed quote. Homeowners should compare the index against 2 to 3 itemized bids once the scope is clear.
Related indexes
Compare nearby project types
Related service indexes help homeowners understand tradeoffs before locking scope.