First off, there is a big difference between a steamer and a hot water pressure washer. They both heat up regular tap water up but a pressure washer takes longer to get the job done and can easily damage roof shingles. A high temperature pressure washer, depending on the manufacturer can heat water temperature up to 250 degrees. The problem is most commercial hot water powerwashers output at least 5 gallons of water per minute. A steamer on the other hand will heat water up to 300 degrees an outputs less than one gallon of water per minute. This allows the steamer to cut into the ice dam so you can remove large chunks of ice at one time.
If you come across this article you are probably trying to educate yourself on how to remove ice dams from your roof and gutters. You probably came across several other articles that refer to mechanical methods, which are tools you can use to alleviate the situation. While we would not recommend tackling a job like this on your own, ice dam removal contractors may use chain saws, sand blasters, hammer, axes, screw drivers and ice picks. You probably also came across articles referring to compound methods, which are chemical ingredients that can get the job done like salt, dry heat, ice melt, roof tablets, or calcium and magnesium. You may have even come across bizarre methods like heat cables and blow torches.
Well, the problem with compounds is if you are inexperienced you can damage your roof or gutters. Most of the compounds like salt and roof tablets are meant to prevent ice dams, not get rid of them. If you are even successful in getting roof tablets up on your roof (through a window or with a ladder I imagine) it is difficult to have them remain in once place. Remember, you are putting them on ice so they can easily slide off. The problem with blunt objects like axes and ice picks is that you can easily damage whichever material is under the ice. The same can be said about heat cables in addition to the obvious safety hazards involved. As per one instance in which I came across someone using a blow torch to melt an ice dam, this is just crazy. You can melt whatever is under the ice dam whether it is your roof or your gutter.
So what does all this mean? It means you should educate yourself on how to prevent ice dams so you don’t have to worry about getting rid of them. And, if you come across an ice dam you should call in an expert pressure washing or ice dam removal contractor who has experience.