Steaming an ice dam is pretty simple work, like using a chain saw. A professional will make it look easy because for the most part it is. There are a lot of ways to damage a home while using a steamer, however, so experience is key.
Without question, steaming remains the most efficient and most effective way of removing ice from roofs. Methods involving chisels, hammers, hatchets or ice melting compounds are not advised because of the many potential hazards they present to your roof and home.