Steep Roofs and Ice Dams

The following is an excerpt from the article “Preventing Ice Dams on Businesses.” For more information please visit


  • If the building has a history of ice dams, removing the snow will remove the source of a potential ice dam.
  • A roof rake may be used for most single story buildings while remaining on the ground to pull snow down the roof slope.
  • Do not pull snow back against the slope or sideways since the snow may get underneath the cover and can break shingles.

For buildings with a history of ice dams with roofs that cannot be reached with a roof rake from the ground, consult a roofing contractor. Occupational Safety and Health Association (OSHA) regulations and standards should always be followed when working on a roof. Fall protection should always be implemented when working on a roof.

Remove or relocate heat sources that are installed in open areas directly under the roof, such as an attic or mechanical room. A warm attic melts snow on the roof, causing water to run down and refreeze at the roof’s edge where it’s cooler.


  • Soffit/ridge vents provide good ventilation for gable roof systems, however due to retrofit costs they are not always a practical solution for existing roofs.
  • Gable end vents are not quite as effective as soffit/ridge venting, however they are cost effective.
  • Electric fans can placed over the gable end vents to increase the flow of air. Box or static vents are practical improvements for hip roofs.
  • Recessed light fixtures in the ceiling below the open area that is directly under a roof, such as attic space, should be insulated to prevent the release of heat into the attic.
  • Check to see if there is any visible light from recessed light fixtures in the attic. If there is visible light, they are not adequately sealed or insulated.
  • Insulate or seal all attic penetrations such as partition walls, vents, plumbing stacks, electric and mechanical chases, and access doors.
  • If the roof covering is going to be replaced in the near future, ensure that a sealed roof deck is installed using at least two layers of underlayment cemented together or a self-adhering polymer modified bitumen sheet (similar to underlayment).
  • The sealed roof deck should extend from the edge of the eaves to at least 24 inches beyond the inside of the exterior wall. See Sealing the Roof Deck

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