Preventing and removing ice dams is critical. Damage to your home’s roof from excess snow and ice buildup can ruin your winter season. Even if you’ve winterized your home, an ice dam may still form on the edges of your roof – and it can be a nightmare waiting to happen.
Ice dams can form slowly and unexpectedly – unless you know what to look for. If left unchecked, melting ice water will find its way into your home, costing you thousands in repair bills.
What Is an Ice Dam?
An ice dam is a thick band of ice that forms along the edge of a roof, preventing water and melting snow from draining properly. Since water cannot drain, it backs up and can be forced beneath the shingles, leaking into your home. Water entering in this manner can have multiple exit points, causing damage to walls, ceilings, and insulation.
If you’ve never had an ice dam, you should still be prepared given they can form at any time under the right conditions. Prevention is key, and simply knowing what to look for is crucial.
For example, the formation of large icicles or a ridge of ice along a roof’s edge is a sure sign of potential problems. If you see ice build-up in typically ice-free areas, you almost certainly have an ice dam in progress. Common areas to check are the sides of exterior walls and along exterior vents, window frames, and soffits (the underside of the eaves).
How Ice Dams Form
The earlier you can detect signs of ice dam formation, the better you can prevent damage. Here are several causes.
- Poor Insulation and Ventilation. Poorly installed insulation won’t allow proper ventilation, often causing too much warm air to leak into your attic. When excessive heat builds up, the snow on the roof melts. This can occur beneath a thick blanket of snow on your roof, completely obscured from your view on the ground. As meltwater runs off, it freezes near the edges since the last 6 to 18 inches of your roof is often colder.
- Mild Daytime Winter Weather. Winter days with temperatures just above freezing and nights that fall below 32 degrees result in a cycle of thawing and freezing on your rooftop, promoting the buildup of ice.
- Flat-Pitched Roofs. Roofs that angle at a flatter pitch are more prone to having ice dams than steep roofs since water drains off less effectively.
- Deep Snow Piles. Thin patches of snow here and there are hardly cause for concern. However, a substantial snowfall producing four to six inches or more on your rooftop can be dangerous – especially when combined with other conditions that contribute to ice dam formation.
Remember, no matter how well you’ve insulated your attic, heat leakage can still occur from your living space into the cavity between your ceiling and your roof – especially if you keep your house unusually warm.
Ice Dam Prevention
Don’t wait until water leaks into your home causing structural damage. A little bit of preventative maintenance can go a long way in keeping ice dams from ever forming.
1. Use a Roof Rake
The best way to prevent an ice dam is simply to remove the snow from your roof before it has a chance to melt and refreeze. A roof rake is all you need.
A roof rake is essentially a flat shovel at the end of a long pole, often with extensions to make it even longer. These rakes allow you to pull snow off your roof while standing firmly on the ground.
Roof rakes work best when removing fresh, fluffy snow rather than wet or hard snow that has solidified. You can get most (if not all) the snow off the roof of a one-story house using a roof rake. Two-story homes are more difficult, but even removing snow from the last few feet of your roof can go a long way.
There are several types of roof rakes on the market – most sell for $30 to $80. Some have wheels on the blade to prevent damage to shingles, while others have telescopic handles rather than rod extensions for a quicker height adjustment.
2. Install Heat Cables
Electric heat cables are installed along the edge of a roof to melt snow before an ice dam forms. Do-it-yourself heat cable kits are available from many home improvement supply retailers. How much they cost depends on the size of your roof and the length of cable you need, but generally, a heat cable kit can cost anywhere from $20 to $200, not including the added tools you may need to buy to finish the job.
3. Improve Attic Insulation
The best way to permanently address the problem of recurring ice dams is to improve the insulation in your attic. This does not mean piling on more insulation, as a poor job, no matter how much insulation you use, will not stop the ice dams from forming.
Instead, focus on plugging gaps, realigning improperly installed insulation, and stopping the trickle of warm air from areas such as light fixtures, conduits, and electrical outlets. These measures can make a big difference, though calling a professional is often required.
4. Improve Attic Ventilation
To further cool your attic, you can improve ventilation by installing ventilation systems. There are many options, including soffit vents, attic ventilator fans, and turbine ventilators. However, installation likely requires professional assistance.
Ice Dam Removal
If you find yourself with an ice dam, removal should be an immediate priority. The following methods should alleviate the problem until a more permanent solution (such as making structural changes) can be implemented.
1. Chip and Hammer
Chipping away at the ice is typically very effective. However, you are at high risk of unintentionally damaging your roof. Therefore, when selecting a hammering tool, choose wisely: an ice pick might be a better choice than a hatchet to preserve your shingles. And a rubber mallet, while less efficient at breaking up the ice, might be much better for your roof than a claw hammer.
Rather than completely breaking apart the ice dam, it may be enough to create channels for drainage. This is only a stopgap measure, but you need to divert leaking water as quickly as possible.
2. Spray Warm Water
A spray bottle filled with warm water can work wonders. Trying to melt a thick ridge of ice this way may not be feasible, especially if the ice encompasses the entire perimeter of the roof. However, this method can be effective if you focus your ice-melting efforts on specific problem spots.
3. Apply Chemical Deicer
Chemicals can clear a roof dam quickly. Unfortunately, depending on the product you use, they may harm or discolor your roof while causing damage to sensitive shrubs or plants.
Take proper precautions by checking the labels of deicing products for possible warnings, and cover your garden plants with a tarp for protection. Generally, calcium chloride-based products are safer than other chemical deicers. Avoid sodium chloride-based products or rock salt as these will surely damage your roof due to their corrosive properties.
4. Place an Ice Dam Sock
Creating drainage channels can be a good temporary fix to ensure that water does not leak into your house. To do so, create an ice dam sock with chemical deicer and women’s nylon stockings by following these steps:
- Fill the stockings with calcium chloride and tie the open end so it will not spill out.
- Identify the sections of roof that are your biggest trouble spots.
- Climb a ladder and carefully place the nylons on the ice dam perpendicular to the edge of your roof, several feet apart. The calcium chloride in the stockings will react with the ice, forming channels in the ice dam within several hours. If you prefer not to use a ladder, pitch the nylon stockings onto the edge of your roof. Tie a long piece of string to the end of the stocking to position it and eventually pull it down.
The nylon stocking method works very well, but eventually, the calcium chloride in the stocking will completely dissolve, allowing the channels to refill. However, it’s a workable short-term solution until you can permanently eliminate the ice dam.
Call a Professional
If you have immediate water leakage or simply do not feel capable of removing an ice dam, call a professional roofer, contractor, or ice dam removal company (which do exist in places with colder climates). Keep these question in mind when determining who to hire:
- Is the company or individual an experienced professional?
- Which methods will be used? Is there a risk of structural damage to the roof?
- Can you set a specific date and time when the work will begin?
- Is the company or individual insured?
Many professional ice dam removal companies use steam to quickly and harmlessly melt ice dams. However, less-reputable contractors may use metal shovels or high-temperature pressure washers which can harm the integrity of your shingles. Again, always determine which method will be utilized prior to hiring.
With ice dams, it’s always wise to take safety precautions. Avoid climbing entirely onto the roof and make sure you have assistance when using a ladder. Winter is the most dangerous time of year to be doing this kind of work, so be careful and stay safe.
Do you have any additional tips to prevent or remove ice dams? Any horror stories?