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.
With so many architectural challenges by poor designs, dormers, gables, cathedral ceilings, getting to a cold roof via ventilation can be difficult and extremely costly. Your article does not address a basic fact of Mother Nature… THE SUN. What do you do about radiant heat from the sun everyday? Most homes will see some sun exposure during the day. That heat melts snow and creates moisture on the roof, typically following the slope to the eaves and valleys. Then the temperature drops and the melt refreeze. If this happens over a couple of days… ICE DAM! Even on a metal roof keeping valleys, eaves and gutters clear can only be achieved by keeping the refreeze from occurring by keeping the melt liquefied and allowing it to get off the roof and then too the ground. There are products out on the market that can prevent ice dams and keep them from forming. Checkout http://www.thermaltechusa.com and see them in action.
Comment by Darin Rohead — February 11, 2010 @ 4:07 pm
Thanks Darin. You are absolutely correct. I think you guys have great products and I have recommended them before and will in the future as well.
Comment by toddmiller — February 11, 2010 @ 7:03 pm