The answer to 'why is my roof ice dams' is that ice dams form when snow on your roof melts unevenly, causing water to back up behind a ridge of ice at the roof's edge. This is a common problem in cold climates, especially on homes with poor insulation or ventilation. Ice dams can lead to water leaks, damaged roof shingles, and interior water damage.
Some common causes of ice dams include inadequate attic insulation, poor roof ventilation, and heat loss from the home's interior. Symptoms include icicles forming along the roof's edge and water stains on interior walls and ceilings. Solutions may include improving insulation, sealing air leaks, and using roof de-icing cables or heating cables to melt the ice dams. In severe cases, you may need to call a professional roofer to remove the ice dams and make repairs.