Ice Dams: How They Form And How To Prevent Them

The term "ice dam" describes the phenomenon of ice forming along a roof's eaves and building up inside the gutter. They're created when snow sitting on the roof melts and drains into the gutter, but the water can't flow freely to the drain spout. The water freezes and a cycle is created where an ice block gradually builds up. If left unattended, it will spread to the roof or flow over the gutter and create icicles.

The formation of ice dams can create property damage and a safety hazard, so it's critical to understand how they form, the hazards they pose, how to prevent them, or what actions to take if you have one.

The primary source of warmth that causes snow to melt is excess heat leaking from the building. Improperly insulated attics, gaps in the building's structure (especially older ones), damaged roof shingles, and unsealed vents, such as the bathroom exhaust vent, generate heat.

The extra weight of the ice can cause damage to the gutters, even collapsing them if the ice is heavy enough. If the ice backs up and forms on the roof, it can damage the shingles, and water can seep inside the home, creating issues in areas that aren't noticeable on a daily basis. If left unattended, a cycle is created where additional shingles are damaged, causing the ice dam to creep further up, leaking more water into the home's interior.

When ice dams flow over the gutter, icicles form, indicating a serious issue needing immediate attention. As pretty as they may be, they threaten the safety of anything below them when they fall.

So, what can you do to prevent ice dams? Fortunately, since the cause of ice dams is simple, their prevention is equally simple and can be addressed well before winter.

1. Check the insulation in your attic to ensure there is proper coverage. You want your attics cold in the winter so they don’t heat the roof!
2. When checking the insulation, look around the attic for daylight coming through the structure. Plug the areas where you see daylight since those are sources of heat leakage.
3. Keep the gutters clean and do one last seasonal check after the last leaves have fallen in Autumn.
4. As you're cleaning the gutters, check for areas of weakness where the gutter may collapse if an ice dam forms.
5. Install gutter guards to reduce the amount of debris that falls into them.
6. Install an ice/water shield on the roof.
7. Improve ventilation under the roof to clear out hotspots.
8. Ensure the seals around exhaust ducts, service cables, chimneys, etc., are sealed.

If you couldn't perform preventative measures, inspect your gutters after a snowfall and check for ice buildup. It may be as simple as checking for icicles.

If you see an ice dam forming, you can take immediate action to reduce the threat of damage.

1. Inspect the inside of the building in the area where the ice dam formed. Check for water leakage, damage, and the source of the heat loss.
2. Remove the snow on the roof in the ice dam area if it's safe to do so. Since removing snow from a roof can create safety concerns, you should hire a specialist.
3. Don't try to break up the ice dam. You may damage the gutter or roof. Also, chipping away ice while standing on top of a ladder in winter conditions will put you in a hazardous situation.
4. Don't try to melt it by sprinkling it with rock salt. Rock salt is meant for driveways and sidewalks and can damage your shingles and kill vegetation below. Instead, use a calcium chloride-based ice melt designed specifically for rooves.

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An ounce of prevention beats a pound of cure. It’s best to take preventative measures before winter falls. If you’re faced with an ice dam situation, your safety comes first, and we recommend having a specialist remove the ice dam before it becomes an issue.

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