The Old Man Winter is officially here, with many places in the US experiencing sub-zero temperatures, heavy snow fall, and hence ice dams on roofs of many homes with inadequately insulated and poorly ventilated attics. Has your home been affected by ice dams? If so, never fear! This guide will show you what can be done to stop ice dams once and for all! 😉
Ice dams can often form on a roof after a heavy snowstorm followed by the onset of low temperatures. Ice dams form when snow at a peak of the roof begins to melt (usually due to warm air rising up in the attic and warming up the top of the roof), which causes all the melted water run down the slope of the roof until it refreezes as it reaches the colder surfaces at the eaves (the edges, or overhangs) of your roof.
Ice dams can easily cause some very costly water damage to your roof deck, attic space, insulation, interior walls and ceilings. When an ice dam forms at the eave of your roof, it blocks off water and causes it to rise up underneath the roof shingles thereby penetrating inside your home. The water will generally rise up faster on the roofs with lower roof slope. The damage caused by ice dam built up can be very costly. You may be required to replace wet insulation, damaged dry walls and ceilings, remove mold, and replace rotten wood in your home. It is obviously, much easier, and far less costly to stop ice dams before they happen!
Cause and Effect
Before you can prevent ice dams from forming on your roof, you need to understand the mechanism behind the ice dam formation. In the winter, your roof gets covered with snow, which is pretty normal. Ideally, this snow would eventually evaporate in the sun, as often happens on roofs of abandoned homes or empty buildings.
Whenever there is snow accumulated on your roof, warm air from inside of your home rises up into the attic space. Once in the attic, the warm air continuous to rise up until it reaches the top or peak of the roof. It is then that the roof surface starts to warm up, which causes melting of the snow on top of the roof. Consequently, and water formed by the melting of the snow runs down the surface of the roof underneath the snow-pack. When the melted water reaches that colder area of the roof, it refreezes forming a wall of ice.
This wall of ice is called an ice dam. The ice dam traps melted water, and eventually cause it to rise up underneath the shingles, which allows it to get inside your house and cause extensive water damage to your property. – The damage may not be immediately apparent, as water often gets absorbed by the insulation in your attic space, insulation in between the wall cavities, and finally, dry walls, plaster, and ceilings.
Potential Damages to Keep in Mind
The insulation that has been exposed to water gets wet and can no longer insulate your home properly. Any wet insulation needs to be replaced. Any damage to dry walls, and any rotten wood will also require replacing. If you do not take prompt measures, then a mold growth can occur behind your walls without you even knowing about it!
How to Stop Ice Dams
Because it is the warm air that makes its way into the attic space and causes the snow on top of the roof to melt, we need to find a way to insulate the attic space and keep it cool in order to stop ice dams from forming. The goal is to have a cool attic space with the temperature at or below 30° F.
There are two ways to keep your attic space cool; insulation, and ventilation. You will find that most older homes do not have sufficient levels of insulation. Many of the older homes do not have an adequate ventilation, either.
Attic insulation requirements
For most homes located within a snow belt zone, a minimum attic insulation level equivalent of R – 49 is required in order to provide sufficient level of installation for your home. Most homes built before the 1980s will not have sufficient levels of attic insulation, nor will they have sufficient levels of wall insulation for that matter.