Garage to ADU Conversion in Oakland, CA

[Teddy Smith]

Hi All

I have a large garage in my single family in Oakland, CA (approximately 400 sf) that I want to convert into an ADU, preferably a 1 br. Want it permitted and separately addressed and separately metered, ideally.

I'm hoping to get some guidance here. It looks like I'll be able to borrow $100k to build it, and I've gotten quotes from 3 contractors and one came in at $80k, one at $130k and one at $200k.

I'd love to go with the one at $80k, but the range of pricing has me worried because if the $80k guy doesn't come in at $100k or less, I don't have any extra money.

Does anyone have any advice on how much this should cost with a reasonable contractor?

Recommendations of reasonably priced licensed GCs are welcome.

And more broadly I would like some feedback on if this is a good idea, if building a separately permitted and separately addressed ADU of 400 sf for $100k or less is doable.

Also feedback on doing it unpermitted and why that's something I should consider.