Ice Dam Prevention, How to Stop Ice Dams

The winter time brings us cold weather, winter holidays, and sometimes lots and lots of snow with heavy snowstorms and low temperatures. Unfortunately, with the snowfall, we also get the unsightly ice dams and icicles hanging down from the gutters of our homes. The major issue with the ice dams on the roof, is that they trap the melting water running down from the top of the roof, and cause it (the melted water) to rise up underneath the roofing shingles and seep through inside our homes.

How do ice dams form on the roof?

The heat from the house rises up into the attic where it continues to rise reaching the apex of the roof. The warm air warms up the top of the roof, which causes the snow accumulated on top of the roof to melt. The melted snow turns into water, which runs down the roof surface underneath the snow-pack. When the water reaches the colder edges at the bottom of the roof, it refreezes forming a wall of ice. This wall of ice is commonly referred to as an ice dam, because it traps the melting water.

Misconceptions and Important concepts

Although, ice dams can sometimes reach the gutters, they do not form in the gutters, but rather they form at the eaves of the roof. If you can get your attic air temperature to 30° F, or lower, then you should be able to eliminate ice dams from happening in the first place.

Preventing Ice Dams

First and foremost, your roof needs to have at least 2 feet of ice and water installed at the eaves and in the valleys of your roof. The ice and water gets installed underneath and prior to the installation of roofing shingles on your roof. The rest of the roof should be covered with a roofing felt also known as a roofing underlayment. Finally, the asphalt shingles upon your roof need to be properly installed.

The easiest long-term solution to preventing ice dams is to minimize the impact of the warm air that contributes to ice dam formation on your roof. One effective way to stop the warm air from escaping into the attic is to use a proper insulation on the attic floor. You will find that most older homes do not have sufficient levels of attic insulation. To further complicate this problem, many homes with the insufficient attic insulation also have many air leaks and subsequent home-to-attic warm air drafts that literally drive the warm air inside the attic.

Step 1 Locating the air leaks leading up into the attic

Locating and properly insulating all the little pathways through which warm air rises up inside the attic is critical for an effective long-term solution to ice dam problem. You will want to properly identify and seal these holes. Use the weather stripping to properly insulate and seal all the little holes through which the warm air escapes into the attic.

Ice dams can cause thousands of dollars of damage to your home. The typical damage caused by the ice dams involves wet insulation that needs to be replaced, damaged walls and ceilings, dry-walls, and plasterer, and all the invisible damage in the form of dampness, growth of mildew, and rotting of the roof deck.

The next step is to bring up the level of the attic floor insulation to a level specified by the Energy star governmental agency. You will find that for the majority of homes within this snow belt zone, the required level of attic insulation should be equivalent to R - 49 value. Once again, most older homes are not properly insulated, which means that you will have add additional attic floor insulation to your home's attic. Before you can add additional insulation to your attic, you will have to find out the current level of insulation in your attic.

Finding out the existing level of insulation in your attic

Grab a simple ruler, and measure the height of your attic floor insulation. Then, multiply the height in inches by 3.14. This will give you the present R - value of insulation in your attic. If the level of insulation in your attic is not sufficient, than head out to your local home improvement center and purchase additional levels of energy efficient attic floor insulation for your home.

A word of Caution

Do not lay, nor push the attic floor insulation into the corner where attic floor and roof walls meet, because it will create a cold area at the edge of the roof, which could contribute to the ice dam formation. Further, you do not want to block the air in-flow through the soffit vents located at the edges of the roof.

Attic Ventilation

Once your attic is properly sealed and insulated, it is time to ensure that your attic is also properly ventilated. First, check to see if your roof has the soffit vents installed. If that is the case, then you're in great shape because soffit vents help drive the cold air inside your attic. If not, then you need to have gable vents installed as an alternative to soffit vents. Sometimes you can get away with installing roof vents in lieu of gable vents. The rule of thumb is to have one square foot of gable ventilation, or roof ventilation, for every 150 square feet of the attic floor. If there are soffit vents, then there should also be a ridge vent installed on your roof.

If there is a gas furnace installed in your attic, then you will need to make sure that it is professionally insulated, and you will also want to have a power ventilation professionally installed in order to help cool off your attic.

Once you have attained an adequate level of insulation and ventilation in your attic, your roof should be in good shape for a major snowstorm, and the onset of low temperatures. If you need a short term solution for dealing with the ice dams that have formed upon your roof, then consider the tools at your disposal outlined below:

Ice dam prevention products

Heating cables can be installed at the eaves of your roof, and turned on during and after a snowstorm to help melt the snow at the edges of your roof, which should help you stop the ice dams. You will have to remember to turn your ice melting cables on and for it to work. You will also have to remember to turn them off before they burn out! Finally, you need to make sure that your heating cables are properly grounded during the installation.

Snow Rakes

You can use the snow rakes to push up and clean up the snow on your roof, which should help you stop the ice dams from forming.

Other alternatives

Once again, those are temporary measures, and you will want to have your attic adequately insulated and ventilated for your long-term eyes than prevention strategy. Keep in mind that by installing metal roofing, which has a special coating that causes the snow to fall off the roof before it has a chance to form into an ice dam, you can completely eliminate the ice dam formation on your roof in the first place! You will still want to have an adequate level of insulation installed to prevent a heat loss from your house.

You will further want to have your attic properly insulated to keep it cool in the summer, and keep the moisture out. Finally, installing an energy efficient metal roof, can help pay for itself over the long run, because a metal roof can last three times longer than an asphalt shingle roof, and can help save you 30% on your cooling costs in the summer. Thus, a metal roof can pay for itself through its longevity and superior energy efficiency.

Further Reading

http://metal-roof.blogspot.com/2008/12/how-to-prevent-ice-dams-on-roof.html

http://www.coolflatroof.com/flat-roofing-blog/ice-dams-prevention-ventilation-of-low-slope-roofs/