This time of year I often get asked whether a metal roof can help someone avoid wintertime ice dams and the resulting damage to their roofs and homes. Generally, the answer to that question is “yes” but there are several things to keep in mind.
First, any time you re-roof your home, it is an opportunity to install an ice and water shield type of membrane around the bottom edge of the roof. Required by code in many places, this rubber or asphaltic membrane will help guard against water intrusion inside of your home if ice damming occurs. However, it does not help keep your shingles from being damaged.
Next, if you have interior damages from ice damming but in the spring your shingles look okay, that does not mean they do not need to be replaced. Some ice damage can be small cracks which, though barely visible, leave your roof extremely vulnerable to water intrusion and further damage.
Third, metal roofs due to their smooth surface and heat handling characteristics, tend to shed snow quickly. This helps avoid ice damming.
The interlocking nature of most metal panels also helps avoid problems due to ice dams.
Finally, if your home is prone to ice dams, when you re-roof is the time to see if you can increase your attic ventilation as well. Keeping your attic at a similar temperature to the outside will go a long way in keeping ice dams from occurring.