Legal Question in Construction Law in California

I'd suggest three things: (1) First, negotiate with your contractor for proper repairs to which you're entitled; if this fails, (2) contact the Contractors State License Board at www.cslb.ca.gov and go to the consumer complaint subheading to ask for advice; and (3) consider having an independent "expert" look at the defective work to give you a written opinion that would stand up in court if need be. Your success in negotiating with the contractor may improve if he knows you've taken steps 2 and 3, and a negotiated solution will ordinarily be more satisfactory for all concerned (cost, time and stress) than litigating. BTW, does your contract call for arbitration of disputes?