Ice Damming

Middle Tennessee residences  have been experiencing a phenomenon called "ice damming" which is commonplace in the north, but unusual in the south.  Ice damming is difficult to rectify in the immediacy and will typically resolve itself when the freeze/thaw cycle subsides.
Dams can tear off gutters, loosen shingles, and cause water to back up and pour into residences. This is will lead to peeling paint, warped floors, stained and sagging ceilings, wet insulation, etc. 
Here is how an ice dam is formed:

1. Heat collects in the attic and warms the roof, except at the eaves.
2. Snow melts on the warm roof and then freezes on the cold eaves.
3. Ice accumulates along the eaves, forming a dam. Melt-water from the warm roof backs up behind it, flows under the shingles, and into the house.

Ice dams will often stop leaking to the interior at night as temperatures drop, and begin leaking again as the sun comes up and warms the roof and attic.    
As difficult as it is to not take action, chipping at ice dams will damage shingles, flat roofs, siding, gutters, etc.  Additionally, it is unsafe to be walking icy or snow covered roofs and in many cases isn't possible. 

There are long term solutions to ice damming that should be taken into consideration:
  • Seal air leaks in the attic to stop warm air leakage (the source of the problem).
  • After sealing leaks, add additional insulation in the attic.
  • Provide adequate attic ventilation so that the underside of the roof and outside air are at the same temperature. Check to make sure attic insulation is not blocking roof ventilation.
  • Clean leaves and other debris from gutters before the first snow. This will help prevent ice build-up in gutters.