Things initially went fairly well...he built the addition, installed a new roof with skylights, and did some interior work.  We paid 4 of the 5 payment installments, as well as additional money for several change orders.  At one point he told us that he couldn't go any further until certain plumbing work was completed.  It took us a while to get that done, and when we did and called him to come finish the work, he started putting us off.  The contract included materials, including siding and decking material.  He never bought those materials.  We repeatedly tried to get him to finish the work, to no avail -- despite the fact that we offered to work with him to change the terms of the contract to pay him more money since he claimed he was having financial issues.  We tried for more than 3 years to get him to finish the work.  In the end, when it became clear he had no intention of working with us, we went with another contractor.  At this point we estimate that although we had paid 4/5ths of he contract amount, he still had 50% of the work to complete, including buying the material for the siding and decks.  We feel that he stole thousands of dollars from us by accepting our money and not completing the work.