Snow on the roof begins to melt from exposure to the sun or heat coming from the inside of the building.As the melted snow flows from the roof to cold gutters and downpipes, it refreezes and forms ice, which continues to build up until it blocks the water flow.This will cause downpipes and gutters to break.In addition, snow water can flow through the roof and into the building, causing structural damage.The snowmelt system protects buildings from snow damage by melting and draining snow and ice from roofs, gutter and downpipes.