SPARTA, Wis. – A kitchen fire spread to the roof and extensively damaged the Great Wall Buffet on West Wisconsin Street. The fire broke out about 4 p.m. Firefighters extinguished it within 30 minutes but stayed another three hours to check for hot spots. Water and smoke damage was serious, said Fire Chief Mike Arnold. The restaurant is surrounded by parking spaces wth no buildings immediately adjacent to be threatened. Traffic on Highways 16 and 71 was detoured 2-1/2 hours.