Honest 2026 pricing for South Bay ADU projects. These ranges are installed cost — design, permit, construction, and standard finishes — based on jobs we've actually closed in this market.
Installed cost ranges
Detached new-build
$500–$700/sqft
Garage / interior conversion
$300–$425/sqft
Why South Bay prices look like this
☐Highest detached cost in our service area — small lots, walk-street access, dump fees.
☐Coastal Development Permit consultant + biology costs commonly $20–60k on MB / HB lots.
☐Palos Verdes geotech (landslide complex) can add $35–100k in foundation engineering.
☐Local design review in Manhattan Beach often pushes architectural fees 25–40% higher.
How to read these numbers
These are total installed $/sqft, not just construction. The detached range assumes a clean 600–900 sqft new-build with mid-range finishes. Conversions price lower because the shell already exists — most cost lives in plumbing, electrical, and the kitchen. Move outside these ranges and we'll tell you why before you sign anything.