Heat tape cables control the accumulation of ice on a roof, preventing ice damage. They reduce the likelihood of water building up behind ice dams by creating escape channels. Heat tape cables are installed in livestock structures to help prevent animal accidents and losses.
Heat tape cables melt channels of ice, minimizing water from building up in water dams. Water that backs up behind the ice runs off through the channels instead of accumulating under the roofing materials and leaking into the building. The de-icing cables work best at avoiding ice accumulation if they reach to the edges of the lowest shingles.
Ice dams accumulate on a roof when there is insufficient ventilation, lack of insulation or an excess of warm air bypasses the attic. They occur mostly on intersecting roof planes, roof-wall intersections, roof valleys and the roof gutter systems. Contractors may place heat cables over or under the shingles, or use self-regulating heat tapes to maintain flow of water through the gutters and the pipes.
For heat cables to function properly, avoid cutting them, as this changes the wattage and leads to overheating. Lapping cables directly over one another causes excessive heating or may lead to cable burnout. When using heat tape cables, prevent moisture from penetrating into electrical connections.