attic fan: Attic Fans Won't Fix Ice Dams... or Anything Else - 01/15/13 10:13 PM
Icicles hanging over the edges of roofs might look pretty, but once enough melted water gets trapped behind that ice, water can leak in to the house.  Minnesota saw a ridiculous amount of ice dams two and three winters ago, which prompted many homeowners to start looking for ways to prevent ice dams.
The two main driving factors behind ice dams are attic air leaks and insufficient insulation.  If those two are fixed, the potential for ice dams is quite minimal.  A third component to ice dams is attic ventilation.  Attic ventilation is required by code, but it's not an ice dam elixir.  As … (10 comments)