Removing ice dams with open flames can have serious consequences. A two story house near Rockville Maryland sustained approximately $1.5M in damages after a group of workers ignited the roof while trying to remove ice with a propane torch intended to install rubber roofing.
Authorities were called to the 6100 block of Neilwood Drive shortly after noon. It took nearly 90 minutes and 70 firefighters to get the fire under control. Firefighters had to retreat from the inside of the home because of fears it would collapse.
Luckily, no one was seriously injured. One of the workers was taken to the hospital and treated for smoke inhalation.
You should never attempt to remove ice from your home using an open flame. I would avoid hiring contractors who employ this process. There are many experience companies that will safely remove the ice from your home before it damages your roofing system. If you are having problems finding someone in your area, you should search Google or Twitter for recommendations.