The appearance of pitched roofs may change quite dramatically in Calgary, when the outside temperature falls below freezing. Warmth filtering through from living space below prevents snow on upper roofs from freezing, so moisture can gradually drain away.
However, circumstances are different on the lower roof surfaces, where the pitch reduces slightly as it meets the eaves. There, the unheated surface is much colder, meaning the moisture can freeze solid for winter.
More moisture follows and forms a dam that finally traps the snow on the roof. Deicing cables are a popular alternative to clambering up on top with a shovel. However, as we shall show, warming the eaves with live electric wires may not be a perfect solution either.
We Can’t Ignore Ice Dams And Here’s Why
Snow is frozen water and it is heavy. Six inches of snow adds pressure to a roof, and this can be can be deeply concerning. The weight of the snow forces moisture to drip through under shingles, and can cause costly damp repairs when the thaw comes in spring. This is the logic behind fitting deicing cables.
The Ups And Downs of Installing Electric Cables
EFFECTIVENESS
Deicing cables have sufficient electrical resistance to warm slightly, and melt snow when an electric current passes through them. However, this warmth does not travel far, and only snow immediately around the wires melts.
This means the system creates narrow channels through which unfrozen snow melt flows. This could, in theory, help keep the roof clear. Although in practice the homeowner often has to foot the bill for more cables.
PROJECT COST
A deicing system increases a property’s electricity bill when it is running. Although this expense may be mitigated by installing a more expensive, temperature-regulated system that turns on when the temperature falls.
In summary, deicing can be an attractive option when we consider the potential impact of ignoring the risk. Damp in the attic may be something to put up with, but it fades in comparison to a roof collapsing beneath the weight of snow.
Consider These Factors Before Installing Deicing Cables
Weigh effectiveness against project cost carefully before you decide to go ahead. You could save on the cost of installation, if you did the task yourself. The job is certainly not that technically difficult if you are handy.
Experience counts though, and you would need to understand the theory and set the job up right. Valiant Exteriors employs full-time people who know what they are doing. Make sure the contractor you appoint understands electricity well.
More Information
Ice Dams Do Not Need Eavestroughs