Preventing and Removing Ice Dams: A Comprehensive Guide for Homeowners
For anyone who lives in an area that gets a decent amount of winter weather, there are plenty of reasons to think about insulation. Keeping a home's interior nice and warm is certainly important, but keeping the exterior cold is even more so in some ways. Without an adequate barrier that maintains a steady climate for the roof similar to the outside temperature, problems can arise. Specifically, lingering snow on the roof can melt and freeze every day, creating an ice dam — a common problem for many homeowners every year.
Ice dams can make a home look like a nice and cozy postcard, but they can cause a lot of damage. If homeowners do not know what to look for, they may not realize how serious the problem is. Without the proper precautions and resources, a single ice dam can cost thousands of dollars and take months to repair. Fortunately, there are ways to stop it from happening. With this information, homeowners will understand how ice dams develop, the most effective ways to prevent them, faster solutions to eliminate an existing ice dam, and tips to avoid causing more damage. If you own property in an area prone to snowy winters, or if you plan on buying a ski home, understanding and addressing the following issues before snowfall can make a significant difference.
Table of Contents
- What Causes an Ice Dam?
- Negative Consequences of Ice Dams
- How to Prevent Ice Dams: Long-Term Solutions
- Trouble Spots & Warning Signs
- Ice Dam Removal
- What NOT to Do
What Causes an Ice Dam?
In areas with moderate winters and regular snowfall, ice dams can be fairly common. Breckenridge real estate is no stranger to ice dams. Many regions have winter temperatures that rise above freezing during the day and drop back down overnight. If there are warm spots due to insufficient insulation or other issues, certain parts of the roof will melt snow more quickly. These warm spots often result due to heat transfer from the furnace, or warmth from a fireplace from inside the home. As the outside temperature gets colder again at night, the melted water refreezes into ice on the roof.
Typically on warmer days, the snow will melt and simply flow off the roof. An ice dam slows or prevents a natural runoff through the gutters. Left too long, it continues to grow. As the dam builds, it becomes more difficult for melted snow to drain away. It extends until it creates pools of melted water that freeze and take up a larger portion of the roof surface. The water may freeze to the roof or pass through gaps in the roofing material and leak inside the home.
Any house can have problems with an ice dam, but it requires a specific set of circumstances. Specifically, the roof must have inconsistent temperatures. This is highly common, especially in older homes with outdated gutters or old insulation. Generally, ice dams will not form unless the warmer spots on the roof are higher. However, this can also be a frequent problem, particularly around chimneys or furnace flues.
Negative Consequences of Ice Dams
Although ice dams may be somewhat difficult for homeowners to spot, they can cause a surprising amount of damage. Roof and structural repairs after an ice dam can potentially cost thousands of dollars, depending on the extent of the damage. The longer the ice dam sits, the more problems it can create. Although much of the immediate risk residents face goes away with winter, the long-term concerns resulting from water damage to the structure may linger for months or years. The potential for structural and physical harm should prompt homeowners to take action as soon as they think an ice dam is forming.
Following the path of melted water helps homeowners to understand how an ice dam can cause so much damage in a relatively short period of time. A new roof that is well-sealed with proper attic insulation may withstand heavy snow, but even this arrangement will not last forever if it is not maintained. Eventually, the roofing material could develop tiny gaps, old flashings around chimneys can wear out and create a leak, and the ice dam can even loosen shingles and increase the likelihood that they will blow off in strong winds. The melted ice and snow eventually pass through these gaps and soaks into the wood underneath.
The roof decking is designed to block some moisture. However, with a pool of water sitting on it for hours a day, it will rot over time and allow moisture to enter the home. It all starts with the insulation. Depending on the region and the type of insulation, it may be several inches thick. Insulation is usually not very dense, which means that it may absorb water somewhat freely. Insulation usually has a vapor barrier to prevent moisture from passing further inside. If this barrier has gaps, or if the water reaches the joists, it can continue to spread to more parts of the house.
Moisture in the walls is insidious. Homeowners often do not realize that there is a problem until the water has quietly progressed through a significant portion of the home’s exterior. If left long enough, it could damage the following parts of the structure, requiring repair or replacement:
- roofing material
- exterior and interior paint
The issue could begin shortly after the ice dam starts to build, but it can continue to expand almost indefinitely. Water damage gets harder to remedy the worse it gets, meaning it is important to take action as soon as possible.
It's also possible for the roof to collapse when enough snow has accumulated on it. Generally, residential roofs can support 20 pounds per square inch before they start to become stressed. This roughly estimates to 4+ feet of fresh snow, 2+ feet of packed snow, or 4+ inches of ice.
Although the most obvious problems resulting from ice dams relate to the structure of the house, there are a number of potential concerns for the residents living in the house as well. The buildup of ice while the area is still generally cold creates icicles. Some of them can be particularly large, extending several feet off the gutters. This can cause a structural instability that could put people at risk for serious injury. Sun shining on the icicles may cause water to pool underneath. If it freezes into ice, it can create a slippery surface. And ultimately, if the icicles get too heavy, they may fall down on someone or even tear off portions of the gutter.
Many possible problems come indirectly from the ice dam. For example, if people try to remove the ice dam without the proper equipment, they may fall from the roof or injure themselves. Long-term water damage in the home promotes the growth of mildew or mold, especially in areas with higher humidity. This is a common cause of chronic allergies, typically shown through coughing, sneezing, or watery eyes. It can also make asthma symptoms worse for people who have it.
How to Prevent Ice Dams: Long-Term Solutions
Since a difference in temperature along various parts of the roof is the major cause of ice dams, removing the source(s) of the inconsistency is the solution. Homeowners can employ three different tactics:
- decrease heat transfer from the interior
- block moisture accumulation from the exterior
- ensure that the roof is regularly maintained
These are long-term solutions, so they are not always appropriate for use during wintertime. Homeowners may need to prepare at least a few months ahead to inspect their homes and carry out an improvement plan.
Preventing heat transfer is the key to reducing the likelihood that an ice dam will form. After all, it is the warm spots created by the higher temperatures inside that cause most ice dams. A systematic approach can help homeowners determine which areas have the greatest potential for issues, so they can address them first.
Insulation is one of the most important items to address. This is because many homes do not have enough insulation for the region, especially if they were built in the 1980s and earlier. Insulation is set by R-value. Most homes with regular snowfall and cold winter temperatures need attic insulation with an R-value ranging from 49-60. Like any other part of the home structure, insulation material may age and require replacement. If it is in good condition, homeowners can add more. Although the attic is the most important place to increase insulation, there are other areas to examine and consider improving, as well:
- exterior walls
- hatch leading to the attic
- chimneys and flues
In addition to insulation, homeowners should evaluate other aspects of the structure for problems that lead to inconsistent heating. For example, air leaks make heat pass through the walls and ceiling more quickly. Leaks in the ductwork can cause as much as 30 percent of the heated air to escape, which goes straight to the attic. Sealing these gaps slows heat transfer. Homeowners who have heat sources located in the attic may want to find a new place for them to minimize the heat in the area that's conducted from them.
Since there are several potential heat sources in the home which require ventilation, inspecting the location and function of these vents can ensure that excess heat flows to the proper places. For example, a clothes dryer uses an air vent that should lead to an exterior wall. Ventilation equipment above a kitchen range should lead through to the roof. If any of these or other vents end and release hot air into the attic, they may lead to excessively high temperatures resulting in warm spots on the roof.
Beyond interior improvements, homeowners have several ways to augment the home’s exterior to prevent ice dams. There are basically two approaches people can take: First, make sure what they have is working properly, and second, install new equipment or materials that work better. Depending on the age of the roofing material and the condition of other aspects of the exterior, homeowners may want to combine these approaches.
Working with what people already have is often the easiest way to start. Since ventilation is such an important way to manage heat transfer, most homes already have ventilation in the soffits and gables. Soffits are parts of the roofing structure that link the edge of the roof with the home’s exterior walls. They usually have holes that allow cold winter air to enter the attic. Vents on the gable ends of the home achieve the same purpose. Blown-in insulation can inadvertently block these vents, particularly if it is not done by a professional. Confirming periodically that the vents are clear and appropriately-sized can promote the proper circulation of air.
Homeowners who are ready to make a few improvements can build in some ice dam preventions at the same time. Although no roof in a snowy region is entirely risk-free, there is some evidence to suggest that metal roofing can minimize ice dam accumulation. Fewer gaps and a smooth surface account for most of the benefit. While replacing the roof, people can add ice or moisture barriers under the roofing material.
Other additions may also help. Homeowners who are not ready to get a new roof might install an ice belt around the soffits, which is a band of metal roofing that allows water to escape. Heating cables, tape or cords conduct heat using electricity around the lower edges of the roof. This equipment can melt an ice dam. However, experts stress that it is not a permanent solution to the problem, and requires careful monitoring for overheating or overconsumption of energy.
Although structural improvements to the home provide the best protection against ice dams, several maintenance tasks can also help to prevent the accumulation. Also if left uncompleted, they can also make ice dams more frequent or more likely to cause damage. Homeowners should create a plan to provide basic roof upkeep throughout the late fall. This will lower their chances of needing to perform any maintenance tasks during the winter.
As a general rule, water will always collect on a textured surface. And the more surface area there is, the easier it is for water to remain on the roof. The gutter is a major problem in this respect. In the autumn, leaves fall on the roof and collect in the gutter. This causes two potential issues concerning ice dams. First, a clogged gutter blocks access to the downspouts which allows water to drain away off the roof. Second, the leaves and other debris provide more surface area for water to collect. Standing water is more likely to freeze and start an ice dam. Clearing out the gutter regularly in the fall and at the start of winter ensures a clearer path for the water to properly drain away.
Landscaping and an annual roof inspection also help to identify and minimize risks. Mature trees may have branches that extend over the roof. Trimming these branches away from the home will reduce the likelihood that snow will collect on the tree and fall onto the roof. And an inspection once a year from a professional can provide valuable information about the roof’s condition and its ability to drain water properly. Missing shingles or waterlogged decking is replaced more easily outside of winter. Finishing all these projects before the first snowfall better ensures a safer winter season. This is one area where buying a ski condo can be less stressful, as the association will often deal with regular maintenance fairly well.
Trouble Spots & Warning Signs
Any place that has a moderate amount of snowfall and cold temperatures over an extended period of time can sustain an ice dam. However, there are a few circumstances that can make the occurrence of ice dams more likely. These conditions relate to the unique features of the home and local weather patterns. If homeowners know the common warning signs and the most likely spots on their homes for an ice dam, they can watch more closely for them. Paying attention can help people know when an ice dam is starting, so they can address it as soon as possible.
The idea of a home with a line of icicles along the gutter is almost idyllic in a lot of people’s minds. In truth, this is a significant warning sign that an ice dam has formed. The longer the icicles get, the bigger the ice dam. Homeowners should look for the following indications that they could have a problem:
- lots of heavy or wet snow in the forecast
- icicles hanging off gutters or siding
- piles of snow extending out from the eaves
- low temperatures that keep existing snow on the roof
- temperatures that fluctuate around 32°F, causing a melting and refreezing cycle
- higher temperatures or minimal ventilation inside the attic
- cold rooms on the second floor of the home
Homes do not need to have a single episode of major snowfall in order to end up with an ice dam. Several days of light snowfall without an opportunity for the entire roof to melt may be enough.
Trouble Spots on Your Home
Several parts of the roof and upper structure of the home may create conditions that favor ice dam accumulation and water damage. Starting from the top and working to the bottom, homeowners should keep a closer eye if they have any of the following:
- a roof structure with a lower pitch, which slows the rate of runoff
- exhaust or ventilation systems that pass through the attic to the roof
- chimneys with improper insulation or leaky flashings
- skylights that allow solar heat gain to melt snow on the outside
- eaves that extend further from the house, making temperature regulation harder
- recessed lighting in the ceiling above the attic using heat-emitting light bulbs
- heat loss from windows that passes into soffit vents and increases attic temperature
- cellulose insulation, which can get wet and compress more easily
These common situations either produce or release heat in a way that melts snow or increases attic temperatures. Most importantly, even a well-built or new home does not always provide a system of barriers to prevent ice dams. If any of these conditions are present, homeowners may be at risk.
Ice Dam Removal
Since an ice dam will continue to do damage as long as it is on the roof, a prompt solution is crucial. Some homeowners may want to consider fixing the problem by themselves, as a way to provide a quicker answer as well as save some money. However, there are several situations in which hiring a professional may be the most appropriate choice. People should always take care to ensure that they can remain safe and protect their home with whichever choice they make. Going up to the roof to remove sheets of ice can result in serious injury or death for homeowners who are inadequately prepared.
Although water wants to flow downward, snow and ice tend to stay put. As such, the goal is to clear any accumulation on the roof. If homeowners are already noticing water damage through the roofing or leaks inside, they may want to use a box fan in the attic to freeze the leaks. This is only a short-term solution until they can remove the ice dam.
Since walking around on an icy roof can be highly dangerous for inexperienced people, it is typically not advised for DIYers. Any method that requires someone to climb up to the roof or make movements on the roof while standing under the eaves requires safety equipment and proper safety procedures. One of the quickest things people can do is clear off the snow with a roof rake. Instead of climbing up to the roof to use a push-broom, a roof rake allows homeowners to stand below, on the ground, and pull the snow off a roof. Many roof rake models feature wheels to keep the rake tines from scraping against and loosening the roofing material. People taking this route should make sure to stand far enough away from the home that they do not pull snow and icicles on top of themselves.
Experts have mixed views about a popular home remedy using calcium chloride and pantyhose. Some homeowners have luck when they fill up a leg of pantyhose with calcium chloride pellets, tie off the top, and place it vertically in the middle of the ice dam. In theory, the pellets decrease the freezing temperature of the water, helping it to melt a gap in the dam to allow standing water to drain. However, some experts claim that this method takes too long to serve as a quick solution. They also say that the pellets could discolor or damage the roofing material.
Hiring a Professional
Homeowners may want to consider hiring a professional to remove an ice dam. As a general rule, getting rid of an ice dam and preventing it from starting again soon after often requires people to go up to the roof. Anyone who does not feel comfortable doing this should look for a pro with proper training and adequate insurance in case something goes wrong.
Apart from the risk of injury, homeowners do not want to damage their roofing while trying to solve the problem. Even the hardiest roof materials, like ceramic or slate tiles, can crack if someone steps on them incorrectly. If they have to climb up, a roofing contractor knows the safest places to walk without falling or causing shingles to shift. Professionals use a few methods to remove the ice dam. The most typical and effective treatment for an existing accumulation of ice is a steamer. The contractors stand on the roof and blow steam against the ice and snow, melting it quickly. As a prevention method after a large snowfall, pros may use a roof rake or snowblower to clear it away.
Homeowners may also want to hire professionals to evaluate their home’s airtightness or perform a home energy audit. Weatherization contractors have a variety of tools that allow them to quickly assess air leaks and temperature fluctuations in the attic or on the roof. This could help people identify where they are most likely to encounter an ice dam, and what they can do to prevent it.
What NOT to Do
Apart from climbing up to or walking on a slippery roof, there are a number of common DIY methods that experts say homeowners simply should not employ. These approaches may cause damage to the roof, affect the landscaping under the eaves, or cause a number of other problems. For example, some DIY groups suggest using a shovel, ice pick, or chainsaw to cut through the ice dam. This is more likely to cut through the roofing material or result in injury.
Many tips involve the use of salt on the roof. Like the calcium chloride in the pantyhose trick, homeowners may toss a salt puck or some rock salt on the roof. A lot of people try this approach first because it is low-cost and easy for almost anyone to do. However, this causes a few issues people should keep in mind:
- Salt’s ability to melt ice depends on its thickness.
- Inches of ice or heavy snow may take the salt too long to be effective.
- Melting water without removing the ice dam only increases the flow of water through any current leaks and gaps in the roofing.
- Salt on a frozen roof or gutter runs off into the landscaping below, ruining the soil.
Gutter covers may seem like an ideal solution, but are often counterproductive. These covers are designed to block leaves and dirt while allowing water to pass freely. In reality, they simply extend the eaves further from the home, providing a larger surface area for the ice dam. Similarly, using mechanical ventilation in the attic can create more issues than it solves. It is not appropriate for areas with higher humidity because it can cause moisture control problems inside the home.
The best time to get rid of an ice dam is last winter. As such, any work that homeowners can do in advance makes it more likely that the roof will survive another season intact. In so many cases, people do not realize that they have an ice dam until the top floor ceiling starts to leak. By this point, there is already extensive damage. The roofing material and decking may no longer be salvageable. Ice dam prevention requires careful attention throughout the winter months, homeowners should look for possible trouble spots and signs that an ice dam could accumulate. People who had an ice dam the year prior should assume that the same will happen again in the future.
Ice dams always have the potential to increase the need for repairs, even if it seems like there is no leak. At the very least, hanging icicles can make gutters crack or fall off the house, risking injury or damage to other parts of the home exterior. Days or weeks of standing water on the roof will soak through and rot wood that will remain weakened even once it dries.
Instead, regular visual inspections and calling in a professional when needed is the best way to avoid costly repairs and replacement. Homeowners should distinguish between temporary solutions and long-term prevention methods. The roof is one of the most expensive and protective aspects of the home. Planning to take ideal care of it during the winter should be considered more of an investment than a chore.
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Listing information last updated on February 24th, 2020 at 3:46am MST.