With the 2010 winter season settling upon the U.S., the Institute for Business & Home Safety (IBHS) is offering guidance on how business and home owners can protect their property from winter weather-related perils.
The National Oceanic and Atmospheric Administration (NOAA) predicts “extreme weather patterns for different regions of the country this winter.” NOAAs forecast calls for the Pacific Northwest to have a colder and wetter than average winter, while the South may be warmer and drier than usual.
Winter storms cost $770 million in 2009, according to insurance industry data. “Last year we saw just how dangerous and damaging winter weather can be,” said Julie Rochman, CEO and president of the IBHS. “Taking steps to prepare your home or business to resist the effects of winter storms will help you avoid costly losses.”
Ice Dams
An ice dam is an accumulation of ice at the lower edge of a sloped roof, usually at the gutter. When interior heat melts the snow on the roof, the water will run down and refreeze at the roofs edge, where temperatures are much cooler. The ice builds up and blocks water from draining off of the roof, forcing the water under the roof covering and into the attic or down the inside walls of the house. This two-step approach decreases the likelihood that ice dams will form or, at least, reduces their size:
· Keep the attic well ventilated. The colder the attic, the less melting and refreezing on the roof.
· Keep the attic floor well insulated to minimize the amount of heat rising through the attic from within the house.
· As an extra precaution against roof leaks in case ice dams do form, when re-roofing install a water-repellent membrane under your roof covering that extends inward 2-feet beyond the exterior walls of the heated portion of the building.
Freezing Pipes
Frozen water in pipes can cause water pressure buildup between the ice blockage and the closed faucet at the end of a pipe, which leads to pipes bursting at their weakest point. Pipes in attics, crawl spaces and outside walls are particularly vulnerable to freezing in extremely cold weather. Frozen pipes can also occur when pipes are near holes in your house’s outside wall including where television, cable or telephone lines enter the house. To keep water in pipes from freezing, take the following steps:
· Fit exposed pipes with insulation sleeves or wrapping to slow the heat transfer. The more insulation the better.
· Seal cracks and holes in outside walls and foundations near water pipes with caulking.
· Keep cabinet doors open during cold spells to allow warm air to circulate around pipes (particularly in the kitchen and bathroom).
· Keep a slow drip of water flowing through faucets connected to pipes that run through an unheated or unprotected space. Or drain the water system, especially if your house will be unattended during cold periods.
Is Your Roof Strong Enough?
The snow load risk of a roof depends in large part on the age of the structure. Older roofs can suffer from corrosion of members and connections which can reduce the ability to resist high snow loads. In addition, buildings with lightweight roofs, such as metal buildings, typically have less capacity to handle a high snow load. For flat roofs, the step-down area between roof sections presents a problem due to the tendency for ice and snow collection.
The best source for determining how much snow load a building can handle is the original design plan. Most roof designs can support at least 20 pounds per square foot. However, design loads can range from 10 pounds to 20 pounds per square foot in Mid-Atlantic states, and between 40 pounds and 70 pounds per square foot in New England.
Guidelines to Estimate Snow Weight
· 10 inches-12 inches of fresh/new snow equals about five pounds per square foot of roof space.
· Three to five inches of old/packed snow equals about five pounds per square foot of roof space.
· Ice is much heavier, with one inch equaling about one foot of fresh snow.
Snow and Ice Removal from Roofs
IBHS recommends that property owners not attempt to climb on their roof to remove snow. A safer alternative is to use a snow rake while standing at ground level. Check your local hardware store or online stores to find snow rakes.
