This is a great article from the Insurance Institute for Business & Home Safety website about Preventing Ice Dams on Businesses.
Ice dams are ridges of ice that form at the edge of a roof or around drains and prevent melting snow from draining off your roof. The water that backs up behind this ice dam can leak into the building and cause damage to walls, ceilings, insulation and other areas. Additionally, when the roof doesn’t drain properly, snow, ice and water remains trapped on the roof, adding loads that put your roof at greater risk of collapse. Read more…