How to Prevent Ice Dams and Avoid Major Roof Damage

How to Prevent Ice Dams

With the winter months upon us in New England, we never know what weather lies ahead. A season of heavy snow storms can result in many homes facing ice dams and the damage they can cause. There are some simple ways homeowners can prevent ice dams from happening and avoid the headaches that they may cause to your home.

Why do ice dams form?

Ice dams are produced when there is a heavy snowfall and your home is not properly insulated. Without proper insulation, hot air from indoor living spaces escape through the roof. This makes the roof warm and melts the snow that has accumulated. As the water melts and runs down the roof, the low outdoor temperature freezes the water along the edge of the roof, creating ice dams. Although icicles are often beautiful to look at, they can cause severe water damage if not removed.

Tips on how to prevent ice dams

  • Never heat your roof. Keeping your roof and attic cold will prevent ice dams because the snow on the roof eventually dissipates without producing a large amount of meltwater.
  • The underside of the roof deck should not exceed 30 degrees F. The best way to maintain low temperatures is by ensuring that there is adequate insulation and that gaps which let warm air pass into the attic from the house are sealed.
  • The attic must also be ventilated so that cold air is introduced into it and heated air escapes rapidly. Some remodeling contractors are under the impression that heat passing through the attic helps prevent ice dams, when just the opposite is true. Although excess heat moving from the attic through the roof rapidly melts snow, once the melt water touches the cold eaves, it quickly freezes and forms an ice dam.

If you have a furnace in the attic, it may not be possible to prevent ice dams. Increased insulation, however, should help.

  • First, insulate the areas between the roof rafters. It is important to keep an air space between the roof deck and the insulation in order to prevent a condensation buildup that can delaminate the roof deck. Prior to insulating, install polystyrene rafter air channels, which are available at home centers.
  • Next, lay unfaced insulation batts or blankets over the furnace’s heating ducts to help reduce the heat buildup in the attic. If there’s a hatchway into the attic, build a cover for it out of rigid poly-styrene insulation.

If the gable and ridge vents do not generate sufficient air movement to dissipate the heat, you will need a motorized vent at one end of the attic to exhaust the heat, and an adequately sized vent on the opposite end of the attic to draw in cold air from the outside

Removing ice dams

In all cases, removing the snow will remove the source of potential ice dams.

  • For low slope roofs or flat roofs, use a heavy duty push broom with stiff bristles to brush off the snow. Never use a shovel or snow blower to remove the snow since they may tear up the roof cover system.
  • For steep slope roofs, a roof rake is recommended for most single story buildings. This is the safest way a homeowner can help prevent ice dams because you remain on the ground while pulling 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.

Having your home ready for a snowy winter can help you avoid the costly damage as a result of ice dams. If you are not sure how your home will withstand the elements, call a professional roofing company for an assessment. They can point out problem areas that can be taken care of now, preventing issues that could damage your home or yourself!

Have you ever experienced ice dams on your roof?

Posted in Ice Dams.

2 Comments

  1. You have explained it very clearly and effectively, Indeed keeping the roof cool is the key to prevent ice dams formation.Ventilating the attic would ensure hot air to escape and cold air from coming in.

  2. One of the best ways to prevent the formation of ice dams is to keep the roof cool and you have very rightly mentioned that attic must be kept properly ventilated so that roof does not get warm and ice does not melt.

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