The answer to 'why is my flat roof ice dams' is that ice dams form on flat roofs due to poor insulation and ventilation. When heat escapes from the home, it causes snow on the roof to melt. The melted water then refreezes at the roof's edge, creating a dam that prevents further drainage and leads to leaks and water damage.
Flat roofs are especially prone to ice dams because the lack of slope makes it harder for snow and ice to naturally slide off. Additionally, flat roofs often have inadequate attic insulation and ventilation, which exacerbates the heat loss and melting issues. Homeowners should inspect their flat roofs regularly and address any insulation or ventilation problems to prevent ice dam formation.