Ice dams occur on the roof of your home when hot air is able to enter the attic, where it will melt the snow on your roof. The water will run down the sides of your roof and eventually freeze again, forming a dam of ice that will prevent water from draining properly off of your roof as more snow melts. Having standing water trapped on your roof by an ice dam can cause leaks in your roof and interior water damage, which can be quite destructive and expensive to fix. Understanding some of the ways that you can proactively prevent the formation of ice dams on your roof can help you avoid dealing with such repair headaches in the future.
The simplest way to prevent hot air from entering your attic and getting trapped underneath the roof is to ensure that your attic is properly insulated. Laying down additional insulation on the floor of your attic – which is the same as the ceiling of your home's interior rooms – can help prevent heat transfer into the attic and ensure that the attic stays cold enough to prevent snow from melting off of your roof. This is something to consider in the event that your roof has suffered a leak or pest infestation in the recent past, as both of these things can damage your insulation and reduce its effectiveness.
In a somewhat similar line of thinking to the above point, ensuring that hot air is not able to collect in your attic will prevent ice dams from forming. Installing roofing vents, or similar vents, in the soffit of your roof can allow outside air to circulate throughout your attic, preventing it from reaching a higher temperature than the outdoors and ensuring that snow on your roof does not have the opportunity to melt.
A last resort for homes that face particularly bad winter weather is to install heating cables on your roof. These cables have a built-in heating element that will clear away snow and ice. In order to ensure that they don't simply create additional ice dams, heating cables for your roof should be installed in the area immediately above your gutters, so that water is able to properly drain off of your roof and away from your home. You'll likely also want to run a heating cable through the gutters to ensure that they do not become clogged with ice and disrupt the drainage route.
Contact your local residential roofing services for more information about protecting your roof from harsh winter weather.