The best solution for an ice dam is prevention. So what can you do to prevent an ice dam?
Good Roof Design
Most homes that we see that have problems have a poorly designed roof with lots of valleys, or crickets (a location on the roof where 2 valleys meet together. Many of these roof problems act as funnels and cannot be properly ventilated and insulated. Many homes in Utah are not Designed in Utah and are not properly designed to handle the snow and ice that Utah gets. Many of Utah’s new home designs are beautiful but are prone to serious ice dams
Having adequate ventilation for the attic space will help to keep the roof surface cold, which will help to prevent snow from melting, which will help to prevent ice dams. Ventilation is required for attics, but it’s the last thing that should be considered when troubleshooting the causes of ice dams.
If the soffit vents are dirty, clean them or replace the grills if they’re painted shut. Grills are cheap. If soffit vents are blocked with insulation, install air chutes at the eaves to prevent the insulation from blocking the vents.
Getting rid of attic warm air leaks sometimes known as warm air bypasses
Attic air leaks cause ice dams. In almost every house with ice dams, there will be attic air leaks directly below the beginnings of the ice dam. Attic bypasses are passageways for warmed air to enter the attic space, and traditional insulation won’t fix this. Air leaks into the attic can come from a number of locations and the best way to combat this is by having an insulation and air sealing company to locate these air leaks and seal them with a number of air sealing methods including foam sealing, caulking, sealing up and insulating areas that are missing insulation.
This is a basic concept that everyone understands; you need insulation in your attic. If there are voids in the insulation, they need to be fixed. If there isn’t enough insulation, add more. The current minimum requirement for new homes in Utah is R-49 to R-60 in the attic. This equates to about 20″ of loose-fill fiberglass, depending on the manufacturer.
Remove the snow from your roof
During the winter if you are concerned about ice dams forming the best thing you can do is to remove the snow off of the roof. Whether you remove it yourself or hire a contractor make sure that it is done in a method that will not damage your roof. Pulling snow off the roof with a roof rake will keep ice dams to a minimum. This becomes a constant chore, but it’s better than dealing with water leaking into the house. Just raking the first several feet of snow from the eaves is typically enough to prevent the formation of ice dams, but in some cases, this will cause ice dams to form higher up on the roof. The trick is to get the shingles exposed to the sun; once that happens, the sun will warm the shingles enough to prevent ice from accumulating.
Raking snow off the roof with a roof rake is a safe way of removing snow, as long as you don’t get too close to your overhead power lines. In theory, a roof rake could cause some premature wearing of shingles by removing the aggregate, but it’s not a big concern of mine. Some roof rakes have little wheels at the bottom that prevent the rake head from actually rubbing on the shingles. Removing snow from the eaves is an effective way to prevent ice dams, but it won’t work 100% of the time. I have personally inspected several houses with ice dams forming right where the snow stopped being removed. This is not typical, but it can happen during especially cold, snowy winters. The fix for this is to have all of the snow removed.
For two-story homes where using a roof rake from the ground isn’t practical or possible, the options are to risk your life getting up on an icy roof to shovel the snow off, hire someone else to risk their life or install roof de-icing cables as a preventative measure.
Heat cable or Electric deicing cables
If fixing the causes of ice dams isn’t a possibility and safe removal of snow isn’t possible, de-icing cables or de-icing panels may be a good choice. Sometimes this is the most cost-effective way to prevent roof leakage from ice dams.
Roof de-icing cables, also known as heat cables or heat tape, should be considered a last resort when it comes to preventing roof leaks from ice dams. De-icing cables themselves aren’t cheap, it costs money to have them professionally installed, and they’ll cost money to operate; between five and eight watts per foot.
On the flip side, de-icing cables are very effective. When de-icing cables are properly installed and operational, ice dams won’t cause leakage. De-icing cables won’t prevent the formation of ice at the eaves, but they’ll keep enough ice melted to create drainage channels for water.