Ice Damming & What to Do About It

We’ve had some unusually severe winter weather lately here in southwestern Pennsylvania. During our recent inspections, we’ve seen enormous icicles hanging from roof eaves, along with curled snow sliding off the edges of metal roofs (I’ve attached a few photos for your viewing pleasure). A lot of what we’ve been seeing is something you’d literally have to see for yourself to believe because it could otherwise only be conjured up in your imagination.

One of the biggest concerns with this type of weather is ice damming – especially if you have a typical asphalt shingle roof. If you came across this blog article without already being a subscriber, chances are it’s because you searched for information about ice damming and may even have active leak damage. I hope not, but at least this article will help you to understand what ice damming is, why it happens, and (most importantly) how to prevent it in the future!

So, what exactly is ice damming? Well, it’s no more than a buildup of ice along the eaves (bottom edges) of a roof. Just like a water dam that is built up to hold back water, an ice dam is a buildup of ice that also prevents water from freely flowing downward. The only difference is that traditional water dams are often a good thing, whereas ice dams are never good!

The next most obvious question is what type of damage ice damming can cause. For one, long icicles can form and hang from gutters, which can weigh them down causing them to sag or even pull away or detach. The icicles themselves are hazardous because they can break off at any time and seriously injure anyone that may be standing directly below. Remember Ralphie’s excuse in A Christmas Story when he blamed an icicle for hurting his eye so he wouldn’t get his new Red Ryder BB gun taken away?

The type of damage that people often get most concerned about, though, is leak damage from ice dams. When the perfect conditions occur, leaking can happen fairly quickly, making ice dam prevention all the more important. If ice builds up along a roof eave and a thick layer of snow exists above the shingles, the bottom layer of snow can melt and turn back into water. This happens because the thick snow above actually acts as an insulator and the warm air rising from inside the house causes the bottom layer to melt while the top layer stays cold. The ice at the cold eave prevents the water from flowing downward, so it has nowhere to go but up (hence the term “backup”). Each row of asphalt shingles overlaps the row beneath, so the water can run beneath the bottom shingle edges and seep into the roof structure below. Once this occurs, it may not take long for the intruding water to rot out the roof sheathing and make its way down onto the ceiling and/or wall below.

OK, so we know what ice damming is and why it happens, but how do we prevent it? If you’ve already had leaking from an ice dam problem, there’s unfortunately no easy (or cheap) solution. The repair work will have to be done, and it will likely be fairly involved and pricey. If you’ve had repairs made or haven’t yet had leaking, there are some pretty simple ways to offset the likelihood that you’ll experience a major ice damming issue in the future, so pay close attention to the following tips!

  1. Consider having heat cable installed along your roof eaves. This cable is often installed in a zig-zag pattern and does just what its name suggests… it heats up to melt ice and snow and prevent ice accumulation. Heat cable only needs to be powered when the weather conditions warrant it, so it won’t add a lot to your electric bill and won’t prove to be a big burden. Heat cable is most often found on asphalt shingle roofs, but it can even be installed on metal.
  2. Smack off those icicles! …but safely and only if you know what you’re doing! You obviously need to be careful when you do this, and accessing higher icicles may be difficult, but it’s a good idea to walk around and safely remove any large icicles that have formed, being certain that you’re paying attention to what’s below them. I’m not suggesting you do anything dangerous, but any icicles that are easily reachable and not directly above something that could be damaged should be removed to prevent unwanted damage. It goes without saying, but be especially sure that you are not directly beneath them and are a good distance away!
  3. If you’ve had to make roof repairs from prior ice dammage (did you like that play on words?) or you’re installing a new roof, be sure that the roofer installs ice and water shield beneath the shingles to prevent leaks from ice dams moving forward. This product is a waterproof membrane, used as an underlayment, and does its job extremely well.
  4. Be sure to check your gutters and clean them as needed – especially in autumn. Leaves and debris typically accumulate in gutters during the fall and will clog the gutters in winter if they aren’t cleaned. This will only serve to prevent adequate drainage and make ice dams form more quickly, and a little seasonal homeowner DIY maintenance can go a long way in helping to prevent large potential problems.

Ice dams can cause big problems, but they’re not a year-round issue and can be pretty easily prevented. Hopefully this article has helped you learn more about prevention, and feel free to comment if you have any questions about ice dams or personal horror stories you’d be willing to share.

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