In the Northeast, we are accustomed to inclement weather and by this I mean SNOW. Snow isn’t only annoying to shovel, but it can cause damage to our homes through the creation of ice dams. An ice dam is a region of ice that forms at the edge of a home’s roof. It prevents the drainage of water (melting snow) from flowing off the roof. Ice dams usually cause water to back up resulting in water damage to your home. Damage usually occurs in walls, ceilings, roofs, and insulation.
Ice dams are formed when roof temperatures fluctuate at different roof locations. The graphic below will aid us greatly in our description.
Ice dams begin to form when ice and snow melt on a high point of a roof. Water then flows down the roof until it crosses a roof surface that is 32° F or lower. At this point, the water refreezes and forms an ice barrier. The barrier blocks and freezes future water flow creating a water backup. The dammed water then enters your home through cracks and imperfections in your roof causing internal water damage.
The key to stopping or slowing ice dams is controlling roof temperatures. This can be achieved several different ways. Sealing air leakage paths in the ceiling is very important. Additionally, installing the appropriate amount of attic insulation is essential. Attic insulation keeps the warm air in your home and allows the attic to remain at the external temperature. This results in an even roof temperature across the entire surface.
Proper home ventilation is equally important. Bathroom and kitchen exhaust vents should be venting outside the home and not into the attic (adding heat and melting snow). Natural roof ventilation can also help maintain uniform roof temperatures as well as reduce the chance for mold and condensation to form.
Bloggers Note: It is important to note that it is very difficult to 
completely avoid ice dams on a home but the above suggestions have been known to help with the problem. Additionally, our product Heated Helmet could help unfreeze your gutters. Heated Helmet has the ability to automatically adjust its heat output to the temperature outside, making it both effective and energy-efficient.
Source: Univeristy of Minnesota
I’ve had what a problem with water, wicking into our home on the second floor,…making the carpet quite wet following snow/ice in the winter. The walls seem ok and the ceiling hasn’t had a problem…mainly the problem is the carpet gets very wet. The roofing company has been back to attempt to find the problem, installed new underlayment and new tile 3 feet up, but no change. I even removed the gutter thinking perhaps that was the problem….but your diagram shows my roof issue quite well!
Any suggestions?
Stephen: If this problem only occurs in the winter and you have recurring ice dams then it seems obvious that this is the culprit. It’s unusual though for water to back up into the home and not affect more than just the floor. Typically you’d see water damage on the ceiling, the wall and in the soffit area. A little more information might help to pin point the problem:
1) How steep is the pitch of the roof?
2) Is there a soffit on the house (an overhang)?
3) If there is, are there vents in the soffit?
4) How much and what type of insulation is in the attic?
We have completed our first winter of ice dam & snow removal, and found this article very helpful. Clients are always happy when the snow is off their roof and dams are melting but want to know why it is happening and how they can stop it.