Site Sections

Learney Flyer

Is your roof or windows leaking with snow on roof?

Here in Torphins, during December and January 2009 / 2010 heavy and stubborn snow fell, with extended low temperatures which resulted in myself and others having problems with ice build-ups in house gutters and eaves. Some had unexplained water leaking in through window surrounds and doors.

The problem is likely a buildup of Ice at the eaves - an ICE DAM
Ice dams can develop under the following conditions:
  • Periods of heavy freezing rain;
  • Moderate or heavy snow conditions with an air temperature below freezing.

    Often houses that have never had this problem in normal "cold" weather, can show signs as the weather worsens for longer period, particularly those with gentler sloping roofs.


    Icicles on gutters are typical
    of ice Dam formation

    Most roofs depend upon gravity to keep water from entering your house. Gravity pulls rain water or snow melt water down the roof over tiles and slates which are separate pieces that overlap, and this overlap enables them to shed water downwards without leaking. This is true of all slate, tile, cement tiles, etc.
    You can easily create leaks in these systems if you aim a garden hose up and underneath them. Simple systems like these work well as long as the water keeps moving down the roof.

    Ice dams, however, cause water to pool above the eaves up under the tiles overlap levels, and leak into eaves or into the house.

    Different roof surface temperatures
    Ice dams form when either the sun, or loss of heat from your home, causes the snow on upper sections of your roof to melt, water begins to flow under the snow on its way down the roof.

    The greater the differential temperature between the warm loft space and freezing outside, the greater can be the problem.

    Ice Forming
    If the air temperature is significantly below freezing, the temperature of the externally exposed roof eaves, gutters, and down pipes are very possibly below freezing. This is especially true of cast iron, shaded or North facing sections.

    When the meltwater from the upper section on the warmer roof surface melts and travels down, under the covering of snow, to hit these cold surfaces, it begins to rapidly freeze. Eventually the eaves, gutters and downspipes are layered in ice. The ice buildup continues to build and the ice becomes thicker. Meanwhile, the water is still coming down the roof surface.

    If the water is flowing at a faster rate than it can freeze, it begins to form a pool behind the Ice Dam, normally still under the snow, and over and underneath the roofing materials at the edge of the roof. It only takes 1-2 inches or less to cause problems on shallow pitched roofs. This water then finds its way to the roof boards or lining, and eventually drip its way into your home. The results can be leaks in and around window, door openings and wall tops, these leaks can be persistent. They are often worse during the day when sunshine snow melt occurs, allowing pooling of water behind the Ice Dam.

    Stopping ice forming
    To stop ice dams from forming some methods attempt to use heated electrical wire which is applied to the lower edge of your roof or which sits in your gutter. Often these methods have little effect. In some instances, they can be dangerous.

    Scraping off the snow as it falls can be effective, although time consuming and hard work.

    Scatering salt or laying porous hessian salt bags on roofs prior or as the snow falls, preventing the water melt freezing unless particularly cold.



    Best solution
    However the most effective prevention method is to ensure the roof space is well ventilated, and hence cold. The freely circulating air ensures all the internal roof surfaces are close to , or the same, as the external (freezing) temperature, preventing differential temperatures and the snow on the upper roof melting. Good ventilation also helps remove water vapour, preventing condensation on internal roof surfaces.

    Poor soffit Ventilation problems


    Help : Stop the leaks NOW
    Methods Found to work

  • Cut channels in the ice dam to allow water to escape
  • Scrape off excess snow 2-4 ft back from the Gutter line at internal leaking areas, spread Rock Salt on this area to break down ice on roof and Ice Dam at eaves.
  • Use hot water to melt the Ice Dam to allow pooled water to escape.
  • Bore holes in the soffit underside to allow water inside soffit to escape externally, rather than internally (and fit air vents later). DO NOT USE A MAINS POWER ELECTRIC DRILL Or OTHER MAINS POWER DEVICE - Danger of Death from escaping water contacting with electrical power

    • very picturesque former poor houses, Torphins
    Add a Link Here