The answer to 'why is my roof vent ice dams' is that ice dams are typically caused by poor insulation or ventilation in the attic, which allows warm air to escape and melt snow on the roof. This melted snow then refreezes at the roof's edge, creating an ice dam that prevents proper drainage and leads to leaks and damage.
Ice dams are a common problem in cold climates, especially on roofs with inadequate insulation or ventilation. Symptoms include icicles hanging from the roof, water stains on the ceiling, and damage to the roof, gutters, and siding. Solutions may involve improving attic insulation, adding roof vents, or installing heat cables to melt the ice dam.