Many homeowners believe that the addition of gutter protection to their home is the cause of icicle formation on their eves. The illustrations below tell the story of how ice forms, with and without gutter protection.
There are TWO main causes for icicles to form on your eaves:
1.) Thermal heat from the sun during daytime hours melting snow on your roof, then in the evening hours when the temperature drops what has thawed and moved down your roof – freezes.
2.) The main cause for icicles forming on your eaves is the result of poorly insulated and ventilated homes. Heat escapes into your attic and heats your roof, causing snow that has collected there to
thaw and create water that runs down your roof and to your eaves, where it freezes and backs up when temperatures drop.