Hey @Amit M.!
I'm building it from scratch. It's going to be about 465 square feet, will be a studio / junior 1 bedroom (will have a french door between living room and bedroom).
Based on the preliminary plans a few months ago, I had a quote from a contractor for $210K. This included adding sprinklers in the ADU (which the fire department is asking for; $14K) and some concrete work to lower the slab foundation.
This also had an allowance to add a second water line ($12K) and a third electrical meter ($5K), both of which might or might not end up being needed.
Plus $6-8K for architect fees, $6K for structural engineering fees, and whatever the permits would end up costing ($8-10K I'm guessing?).
Now that the architectural and structural engineering plans are complete, but before submitting to the city for permits and shelling out the permit costs, I wanted to get more precise bids so I could make a go/no-go decision.
- Harman
P.S. The completed plans now include some seismic retrofit work as well; figure if I'm going to shell out the capital might as well invest a little in peace of mind.