I am a homeowner in California. The GC gave me an estimate for a project that was $85,000 and supposed to take 3 or 4 months to complete. Right before construction started he changed the terms of the project to Time and Materials and after a few weeks his guys were only on site for work one day per week. They worked very slow and made lots of mistakes. The result was that the project went on for 7 months and the final cost was $130,000. I paid him in full because I didn't want a lien put on my house, however I pretty sure that in addition to the poor quality work he padded his hours. To add insult to injury I had to spend lots of time supervising the work, pointing out mistakes and instructing on how to fix them. As this was time and materials I was charged to fix their mistakes. I'm considering stopping payment on my final check. ($22,000). But I risk him putting a lien on my house. It's my understanding that there are two potential violations. 1.) In California Time and Materials contracts are not allowed for residential projects. and 2.) The initial estimate didn't include a notice about his ability to put a lien on my house. At the very least I plan to open an investigation with the California State licensing board, however I doubt I will get any compensation via that. route. Any thoughts on my situation?