Southern California ADU Construction Cost 2022

[Jonathan Gober]

Hello, I have approved plans for an existing detached garage (440 sf) conversion to a two-story 1200 sf ADU. Zip Code: 90720. The plans also include adding 2 bathrooms (177 sf total) to the existing house (1500 sf). I am currently looking for a general contractor and have received 3 quotes so far ranging from 400k - 515k or $290 - $375/sf. This seems way too high. We had a family friend contractor help build my parents house (4,200 sf) in 2018 for around 500k ($119/sf). Unfortunately he is retiring so currently looking for a new contractor. Please help.

[Will Barnard]

$300-$400 per sf range is accurate for this type of work. You are trying to compare building a 4000+sf home back in 2018 to todays rates on a 2 story ADU of 1200 sf. Not apples to apples at all. Prices increased dramatically since 2018, the difference of building 1200 sf vs 4200sf is like a 6 pack vs a case.