How Do Ice Dams Form?

Ice dams are a major problem for many Park City homeowners. Ice dams cause damage to homes and pose a serious safety risk.

Let’s take a look at how ice dams form and what they are.

What Are Ice Dams?

An ice dam is build up of ice that forms on the edge of a roof. Ice dams can grow to thousand of pounds and usually form on the valleys and eaves of a homes roof.

The ice buildup from an ice dam prevents water from properly draining off of a roof and begins to build up as water freezes as it sits still. Ice dams can extend down to the ground if not removed.

How Do Ice Dams Form?

Ice dams form due to temperature differences on a homes roof when not properly insulated. As heat from the living area of a home gets transferred onto a snow filled roof and the roofs surface temperature reaches over 32 degrees, the snow begins to melt and run down the surface of the roof.

When water reaches the overhang of a roof(eave) and drops below 32 degrees it freezes. The eave of a roof will maintain the outside temperature because the does not have heat being transferred to it from the inside of a home.

from the interaction between the amount of heat loss from your home, the outside temperature, and snow cover.

For ice dams to form you need there to be snow on a roof, the outside temperature must be below 32 degrees F on average, and the higher portions of your roof must be above 32 degrees F.

As this happens over and over, the ice dam builds in size and the potential dangers grow.