Why would water damage remediation professionals be concerned about ice dams forming on your roof? Isn't that what a roof is there for? A roof is designed to collect snow—but also to thaw evenly. When snowfall on your roof doesn't melt uniformly, barriers called ice dams form, trapping water on the roof. Leakage into the attic occurs, eventually dripping down through the ceiling into rooms below. Along the way, structural damage and mold growth result. And that's when water damage recovery teams get the call.
Ice dams form because the roof is unevenly warm. Rising heat infiltrating the attic from rooms below accumulates at the underside of the upper roof. Snow near the warmed roof peak thus melts more rapidly. As water cascades down to the colder portion of the roof near the eaves, it re-freezes and creates dams that obstruct flow into gutters. Shingling is constructed to shed water running off the roof—not trapped water pooling on the roof—so water soon penetrates the shingles and leaks into your attic.
The best way to prevent water damage caused by ice dams is to maintain a uniformly cold attic.
- Make sure you have adequate attic insulation to inhibit heat transfer into the attic through the ceiling. Most houses more than 10 years old are under-insulated by today's standards. While the recommended amount varies by climate zone, the generally accepted minimum depth for attic insulation is at least 12 inches of standard fiberglass batts or 10 inches of cellulose loose-fill.
- Insulation inhibits heat transfer by conduction and radiation, but does nothing to stop direct air leakage. Locate and seal structural cracks and gaps in the living spaces that allow warm air to leak into the attic. Use caulking to seal cracks at the joints between walls and along the joint between walls and the ceiling. Also caulk around recessed ceiling light fixtures and anywhere plumbing pipes or air vents penetrate the ceiling into the attic. Make sure to weatherstrip the attic access hatch or pull-down stairs, as well.
For more on the prevention and treatment of ice dams, contact Rytech, Inc.
