Ice dams occur when specific conditions allow snow on a roof to melt and refreeze near the roof’s edge, leading to a buildup of ice. This phenomenon can cause significant damage to roofs, gutters, and interiors of buildings if not addressed.
How Ice Dams Form
- Heat Escape
Warm air from inside the building escapes into the attic or roof space due to poor insulation or ventilation. This warms the roof deck, causing snow on the roof to melt. - Water Flow
The melted snow runs down the roof toward the edges, where the roof is colder because it extends beyond the heated interior of the building. - Refreezing
When the water reaches the colder edges of the roof, it refreezes, forming a ridge of ice. Over time, this ridge grows, creating an ice dam. - Pooling Water
Additional snow melts, and water continues to flow down. The ice dam prevents this water from draining off the roof. As water pools behind the dam, it may seep under shingles and into the building, causing leaks and water damage.
Contributing Factors to Ice Dams
- Inadequate Roof Insulation: Poor insulation allows heat to escape, warming the roof unevenly.
- Improper Ventilation: Without adequate airflow, the roof’s surface temperature can vary, promoting melting and refreezing.
- Heavy Snowfall: A thick layer of snow insulates the roof, keeping it warm from below and amplifying melting.
- Cold Weather: Sub-freezing temperatures at the roof’s edge are critical for the refreezing process.
Prevention Tips
- Improve Attic Insulation
Minimize heat loss by properly insulating the attic to ensure a consistent roof temperature. - Ensure Proper Ventilation
Install vents to maintain steady airflow and prevent uneven heating. - Remove Snow from Roofs
Use a roof rake to safely clear snow after heavy snowfall, especially near the edges. - Install Heat Cables
In some cases, heat cables along the roof edge can prevent ice dams by maintaining warmth in vulnerable areas.
By addressing the causes and implementing these prevention measures, homeowners can significantly reduce the risk of ice dams and the costly damages they bring. Contact Ferreira Exteriors for more info!
