The Winter Ice Dam

Ice dams are a common problem that homeowners deal with in our Wisconsin cold winter climate. An ice dam forms when melting snow transitions from a warm surface to a cold surface, such as along the overhang of a house. The build-up of ice is the result of ice or snow melting on the roof area over the warmer, living area of a building and then refreezes when it reaches the cold overhang of the soffit. This wall of ice at the gutter line creates a barrier for any further melting snow to make its way into the gutter system of the house. This continued build-up of ice can force leaking to occur under the shingles at the edges of the roof. Damage associated with an ice dam are lifted shingles, rotted roof decking and/or fascia and soffit wood, and of course, water leaking into the drywall inside your house.

If homeowners have interior damage caused by severe ice dams, the only option is to remove the snow immediately.  The homeowner can choose to purchase a roof rake and pull the snow off the roof from the ground or choose to get onto the snow covered roof and shovel the snow off with a snow shovel.

Sometimes homeowners find themselves having to “chop” the ice off the roof because of such severe icing.  This is not suggested due to the damage that can be potentially caused by puncturing the roof shingles, damage to gutters, etc.  Damaging the roof could result in further leaks and expensive repairs that could have been avoided.

Solving the Problem

There are three ways to help prevent ice dams from forming on your roof: 1) Adequate attic insulation, 2) proper roof ventilation and 3) the necessary amount of ice and water shield.

  1. Adequate attic insulation.  Most attic spaces are under-insulated, causing the warm air of the house to rise into the attic and melting the snow covered roof quickly.  In our Wisconsin climate, it is advised by the Department of Energy to have attic insulation levels close to R-49 or even R-60.  The attic space should remain cold during the winter, staying approximately within 10 degrees of the outside temperature to minimize quick roof melting that tends to re-freeze quickly at the eave edges.  Sufficient attic insulation levels will not only keep the warm air in the home during the winter months, but the cool air in the home during the warm summer months.
  2. Proper roof ventilation. Ventilation is not only needed to prevent ice dams, but also for the overall health of the home and roof structure.  Improperly ventilating an attic can result in condensation in the attic space, delaminating roof sheathing material and eventually mold/mildew growth.  There needs to be proper intake ventilation (venting at the eave or overhang edges) as well as at the ridge line (roof vents or ridge vent).
  3. Ice and water shield.  When we install a new roofing system, one of the first products that is installed is ice and water shield.  This is a leak barrier, a rubber-like asphalt & fiberglass membrane, that is applied at the eave or overhang edge during a roof replacement project.  The ice and water shield leak barrier is also installed in valley areas, around chimneys, skylights and any other areas of the roof that would benefit from a leak barrier.  The ice and water shield prevents any penetration of water or ice if a severe ice dam were to occur on a home.  When installing ice and water shield above the gutter lines for gutter protection, it is necessary to install the proper amount.  The manufacturer recommends that the shield extend 24 inches within the heated wall of the house.  The ice and water shield also seals itself around nails and will divert any water that penetrates the roofing material to run to the gutter and not into the house.

Let Us Help You

We are committed to helping customers prevent problems with their new roofing system.  We also are knowledgeable in helping customers fix problems with their existing roofing system.  Please request a FREE estimate from our company if you are in need of the services we provide.