Is There Such a Thing as an Ice-Dam-Proof Roof?
Homeowners often ask us whether there’s such a thing as an “ice dam proof roof.” This time, I come bearing good news: a metal roof is a great way to minimize your risk of getting ice dams, especially if you’ve got one with a steep pitch.
Metal roofs ward off ice dams pretty well to begin with, but a steeply pitched metal roof is kryptonite to an ice dam.
On a metal roof, there’s almost nothing for an ice dam to adhere to. It’s possible the ice can get a grip on the raised metal screws, commonly used to attach the metal sheets to the roof deck. But as you’d imagine, those little screw-heads don’t really provide much footing for a multi-ton ice dam to hang onto.
Compare this to a roof that has shingles. Shingles form many small layers, which give snow and ice countless little toeholds to dig into. Think of rock climbers, and how they need little knobs, cracks, and other irregularities to grab onto. Unlike a slippery metal roof, a shingled roof is full of little ridges. With the popularity of architectural shingles these days, there can be even more ridges. These ridges, along with the extreme coarseness of asphalt shingles, can easily hold snow and ice in place.
Metal roofs have ridges, too, but those ridges run top to bottom (vertically) instead of side to side. Wet and heavy snow can and will stick to this metal, but any time the sunlight or the ambient temperature warms the metal, the snow and or ice is likely to slide right off of the roof – unless of course you have snow-stops in place.
Snow-stops are designed to stop sheets of snow from sliding off of metal roofs and landing atop people, vehicles, and/or anything else that you’d just as soon not drop a giant sheet of snow on! Most metal-roofed buildings that we remove ice dams from have these snow-stops in place. While they’re great at preventing mini avalanches, they’re not so great when it comes to preventing ice dams.
It’s still theoretically possible for a metal roof to get an ice dam. Melting snow (i.e. water) can still freeze on the cold overhangs and cause a buildup of ice. So it’s not an 100% ice-dam-proof, but to this day we have never seen an ice dam cause a leak on a steeply pitched metal roof.
Metal roofs are also far less likely to leak as a result of an ice dam. Even if you get an ice dam, there are no shingles for the water to work its way under. The only way for water to leak in is around the screws. Those screws do have rubber washers on them to seal out water, so that shouldn’t be a big concern. Still, no system is perfect, and sometimes the seals fail.
Having a metal roof is like having the entire roof covered with an ice and water shield. In my opinion, it’s even better. It’ll be the last roof you ever buy!
Now…if you do happen to form an ice dam on a steeply pitched metal roof (which is doubtful) it’s still a good idea to have them removed for the sake of safety. The ice may also develop a fault line and break off on its own, or if someone accidentally knocks off an icicle. You don’t want falling chunks of ice and a dead mailman.
In fact, we have to be extra careful when we come to remove ice dams from metal roofs, so that we don’t get crushed by a giant sheet sliding sheet of ice while we’re steaming your dam(s) from our ladders.
Not getting crushed is our problem. But it’s one we may never have to deal with if you get a metal roof, because even if you do get an ice dam, it’s unlikely to cause a leaky emergency in your home. Consider a metal roof.