Ice damming occurs when snow on the roof melts and flows to the eaves, where it refreezes, forming a dam of ice. The trapped water can then back up under the shingles, causing leaks, damage to the roof deck, etc. The leading causes of this are improper ventilation or insulation in the attic. This can cause the loft to be too warm, which melts the snow on the roof, even when the outside temperature is below freezing.
While proper ventilation and insulation can help prevent this issue, it is only sometimes possible to eliminate the problem, especially in areas prone to heavy snowfall. In those cases, installing heat coils in ice dam-prone regions of the roof can help prevent ice dam formation.
The most proactive solution is to have your attic inspected and, if necessary, install heat coils. However, if you notice them currently, the only safe way to remove them is with a steamer machine. This machine uses low-pressure high-temp steam, as high-pressure water can damage shingles.
Another critical aspect of preventing ice damming is using an ice and water barrier beneath the shingles. Most contractors install one row (3ft) along the eaves and valleys, which is often insufficient. At Brookens Construction, we install a minimum of 24 inches inside the interior, heated wall, which is almost always two rows or 6ft installed on all eaves. We also install a row on the rake ends, as recommended by shingle manufacturers.
In conclusion, by understanding the causes, taking proactive measures such as proper ventilation and insulation, and implementing recommended solutions, you can protect your home from the devastating effects of ice damming.