A contractor performed a side job, seventeen years ago, installing a metal roof on a building. The owner recently complained that the paint on the roof is chipping, and they want $4,500 for the repair of the paint. The product used on the roof is out of warranty, although the contractor believes that he may have offered a 20 year warranty. The original roof job only cost $9,000. Is the contractor liable for the cost of repainting, under Minnesota law?