Beautiful Roof Icicles Are Actually Harmful Ice Dams

icicles can cause harmful ice dams on houses


As a kid, waking up on winter mornings meant romping through the fresh fallen snow, building a fort, and maybe starting a snowball fight. As a homeowner, opening the door on a snowy morning more likely evokes some dread: of having to shovel driveways and walks, drive in wintery conditions, and worry about whether the roof will leak. Even the glistening icicles hanging off the roof, while beautiful, can be hazardous to your home’s health.


What are ice dams?

An “ice dam” is another name for the ridge of ice that builds up on the eaves of your roof, creating the structural support on which beautiful, long icicles form. These buildups can cause damage to your gutters and water infiltration along your roof (which can lead to hazardous mold, structural damage to your roof, and damage to the inside of your home). Ice dams can damage your gutters, causing them to sag, detach, or break under the added weight, and detaching ice can rip off shingles, gutters, and even parts of the roof underlayment. Broken or damaged gutters can’t successfully drain water away from your home’s foundation, increasing the risk for basement flooding. Additionally, ice dams can be a significant hazard to anything below, since falling ice is both heavy and sharp!


What causes them?

When it snows heavily, snow sticks to and piles up on the roofs of homes and businesses. If heat is seeping out through the roof of a home, the roof is warmer than the outside air temperature. This causes the bottom layer of the snow, against the home’s roof, to start to melt. On sloped roofs, the melting snow layer trickles down the roof under the snow layer. When it reaches the edges of the roof, which are colder and don’t have warm attic air underneath, the water re-freezes. Over time, a mound of ice builds up along the eaves and along the home’s gutters; in addition to dripping icicles, this creates a dam that traps water behind it. This standing-water situation encourages roof leaks.


My roof is leaking! Could this be caused by an ice dam?

If you’re experiencing roof leaking for the first time during the winter after a snowstorm, ice dams are a very likely culprit. The melting runoff becomes trapped behind the dam, giving it ample opportunity to seep under your shingles. Eventually, it can work its way into your home’s attic, insulation, and exterior walls beneath the eaves. This infiltration can cause your home’s framing and structure to rot, encourage the growth of hazardous mold, negatively affect your indoor air quality, and cause damage to your sheetrock and paint. Over time, water that seeps under the shingles can make its way into your interior walls and across your ceilings, causing staining and visible leakage inside your home. By the time you are able to notice this occurring, your roof and home will likely have suffered significant damage.


How do you prevent ice dams from forming?

Some melting and freezing of roof snow occurs naturally during warmer days and cooler nights, but most ice dams are caused by poor attic insulation, or an aging or damaged roof. Both of these factors contribute to a warmer-than-ideal roof. Keep your roof as clear of snow as possible by using a roof rake or shovel. This is only a short-term fix, however; you must take preventive steps for effective long-term ice dam prevention.

If you’re planning to replace your roof, a great long-term option to prevent ice damming is to install a stone-coated steel roof. In addition to withstanding storms dramatically better than asphalt shingle roofs, metal roofs reduce the adherence of snow; plus, they are better at sealing out moisture problems in the event that ice dams do form. To prevent ice dams completely, you must ensure that your roof stays below 30 °F during freezing weather. Make sure you have appropriate attic insulation and ventilation; if you don’t, you can easily and economically install additional insulation (which will help improve your home’s energy efficiency, too). Sealing all points where heat is leaking from your living space into your attic and installing additional insulation will help significantly if you struggle with ice damming. You can also install heat cables to minimize ice formation and retention on your roof.CTA-Ebook-That's-So-Metal

What should you do if you have ice dams?

If ice dams have already formed on your home, improper removal can cause damage to your roof, shingles, or gutters—resulting in leaks or water infiltration. This kind of damage will require you to make roof repairs or replace your roof during the difficult winter season! Hire a professional to remove existing ice dams without damage. To prevent having to deal with ice dams, prepare for winter conditions as soon as possible before heavy winter snows. Have a roofing professional inspect your roof and your attic insulation, and discuss your options for preventing ice dam formation this winter. Call us at 515-597-ROOF (7663) to find out more about our Huxley roofing services, to schedule an appointment, or to receive an estimate. We proudly serve Ames, Ankeny, Huxley, and the surrounding areas.  

 Talk to a Roofing Professional