The winter of 2014 brought with it a significant number claims related to ice dams. With the next winter approaching, we thought it would be helpful to provide some information on ice dams: how they form, strategies to prevent and/or remove them, and tips on protecting your property from resulting leaks.

Ice dams form when snow from the upper/warmer portions of a roof melts then re-freezes on the cooler soffit/eave area of the roof or the gutters. Valleys are also susceptible to ice dam formation. As the thawing and re-freezing process continues, the layer of ice at the bottom edge builds to the point of holding water. Shingles are designed to shed water that is moving down slope. When water is allowed to stand on the roof, it can migrate through fastener holes and roofing material seams. A few occasional light snows will not likely lead to an ice dam, but a constant cycle of snowfalls followed by thawing temps can initiate the process. The ice dam itself is not likely to cause damage your shingles or home; rather it is the water which seeps through roofing materials that causes the damage.

Residential building codes recommend protection against ice dam build-up in two ways. First, in jurisdictions where snow build-up is common, it requires what is commonly known as “Ice and Water Shield,” or an “Ice Barrier,” which is a self-sealing underlayment applied to the lowest edge of the roof, extending at least 24” inside the exterior wall line of the building.  This barrier protects against water intrusion in the event that a small ice dam occurs.  Second, proper roof venting and insulation requirements work to keep unused attics at a temperature closer to that of the outdoors, slowing the overall roof melt. Along with the benefits of preventing ice dams, proper roof and attic ventilation can prevent condensation build-up in the attic, which may also lead to water damage in your home. Ensure your roofer complies with code requirements any time you have roof work completed.

Once the snow falls, you can take additional steps to prevent an ice dam by trying to keep the roof relatively clear of snow. However, this may not be a simple task. The snow rake, which pulls snow off the roof from the ground with the use of extension poles, is the safest way to remove snow from a roof. It is not necessary to remove all snow, but just enough to reduce the likelihood of ice dam formation at the eves and valleys. Excessive snow raking could remove granules from the shingles and lead to a shortened shingle lifespan.

So what do you do if an ice dam has formed? The most effective way to remove an ice dam may be the steam method.  In this method, low-pressure, high heat steam is used to cut and remove the ice. If you choose to go this route, confirm that the contractor will indeed be using steam. Pressure washers are sometimes used and look very similar to a steam machine; however the high-pressure water can cause permanent damage to shingles.

Another ice-removal method is to apply salt or ice melt to the ice dam in the form of a pre-formed puck, or inside a nylon or sock. While this method can be effective, it is slow, and the salt runoff can cause damage to sidewalks or other cement-based building materials.

Often people are tempted to mechanically remove ice dams from roofs or gutters with hammers, hatchets, or crow bars. We do not recommend this method.  It can be dangerous, as you need to access the dam by standing on the rooftop or a ladder in slippery conditions. It also often causes more harm than good, since the shingles are inevitably struck and damaged during the ice-removal process.

If water has made its way into your home, you will most likely notice it on the exterior walls, possibly in the form of bubbling paint, staining on the ceiling or a window trim, or even dripping water. If you notice these signs, the following can prevent further damage:

  • Move furniture away from the dripping area to prevent transfer stains to the flooring
  • Set some fans or your household dehumidifiers in the area of the leak to help dry it out, and set out containers to catch dripping water
  • Roof raking, even after the ice dam occurs, will reduce the potential for additional melted snow to end up in your home
  • Contractors can help with the ice dam removal and drying of your home, but take care to check references prior hiring anyone
  • Dry-out or water remediation contractors can often employ non-invasive drying techniques, which can limit the size of an overall loss and the disruption to you daily life

Do remember to take a few photos in case you decide to file a claim.

Overall, preventing the ice dam from forming in the first place is the best option. If you must take steps to remove an ice dam, take care that the removal does not cause more damage than the ice dam itself. Contacting a reputable and qualified contractor is a good option if you feel the job is too large or complicated to handle on your own.

— Jeremy Korn, Field Claims Adjuster, Pharmacists Mutual