Reasonable cost for Los Angeles property projects

[Nema Escartin]

Hello BB Family,

Need your expertise as to to whether my contractor presented me a reasonable costs. My rental property is located near USC. I need roofing done and was presented a cost of $28k, exterior painting of $9.5k ( 2 story SFH).

For the one bedroom ADU (ncluding plan/permit), tearing down of existing garage and fence, it will be $230k.

Balance on mortgage is less than $200k and the latest appraisal is at $900k.

I am now approved to refi at the rate of 4.125%

Before I sign the final documents, am I making a sound decision here?  

Any advise will be very much appreciated.