With free Acrobat Reader® software, you can view and print Adobe PDF files.

What causes ice dams to form? Ice dams are formed when heat is lost through the roof from the interior of the house. This heat loss causes snow to prematurely melt when temperatures are still slightly below freezing (32º). As melted snow runs toward the eave of the dwelling, it refreezes because the eave and/or gutters are over an unheated portion of the roof and the surface is the same temperature as the outside air.

How can ice dams be avoided? The best way to avoid ice dams is to have your attic properly insulated and vented so there is minimal heat loss from the heated portions of your dwelling to the attic, and there is sufficient ventilation to bring cold, outside air into the attic space. When the temperature inside your attic is as close as possible to the temperature outside, the only way snow will melt off your roof is when temperatures rise above freezing. Subsequently, the temperature of the roof is the same as the eaves and gutters so melting snow does not refreeze.

Would removing my gutters help the situation? Possibly. However, you have to consider the inconvenience of not having gutters during the rainy season(s). By solving one problem, you may be creating another.

If the attic cannot be properly insulated or ventilated, what is my next best option? Although it will not stop ice dams from forming, interior leaks may be prevented by having an ice-and-water membrane shield (a minimum 36-inches wide) installed along the eaves and valleys underneath your existing shingles. This membrane helps to prevent the water that has backed up behind the ice dams and seeped underneath the existing shingles from eventually seeping into the interior of your home.

Electric heat cables, in some instances, are also helpful in preventing ice dams. NOTE: Neither the ice and water shield nor the electric heat cables are foolproof methods.

If I have leaks occurring due to ice dams, what can be done to immediately stop the leaks? The only real short-term solution is to remove as much of the snow and ice as possible so the roof can continue to drain properly and minimize the amount of water damming up behind the ice buildup. Spreading some type of "ice melt" product (not salt) in the built-up areas may help to facilitate melting. NOTE: Physical removal of the snow is, at best, a short-term fix. With more snow, the freeze/thaw cycle could reoccur within a few days resulting in new ice dams.
It may be tempting for some people to get up on the roof and remove the snow, or to chip ice out of and away from the gutters. This work is dangerous. It should only be done by a professional who is familiar with the use of ladders and other outdoor equipment during winter conditions to avoid fall hazards, and who is familiar with the best - and safest - way to remove snow and ice without damaging shingles or gutters.

My roof has ice dams and is leaking. Was my roof improperly installed? No. Ice dams, or interior leaks caused by ice dams, do not mean that your roof is new or old / installed correctly or incorrectly / or in need of replacement. Virtually any shingle roof can leak if water is not allowed to drain off in a relatively efficient manner. Shingle roofs must shed water quickly as they are not designed to hold water.

My roof is covered with snow but is not leaking. What should I do? Probably nothing. Most homes are built according to proper building codes and can withstand a snow load of approximately 30 pounds-per-foot. The additional weight on the roof should not be a factor unless snowfall exceeds this amount, or you have areas that are susceptible to large drifts. If you feel the ice and snow may be causing structural damage to your roof and/or gutters, you may want to consider having the ice and snow removed.

Does my homeowner's insurance cover ice and snow removal or interior damage from leakage due to ice dams? Some insurance companies may cover these damages. You should check with your insurance company regarding ice and snow damage and removal. (Don't forget to check your deductible.)

Severe winter weather is unpredictable. Solving one ice dam problem after a snowfall may not prevent it from happening after a new snow or ice storm. Every situation ~ and every roof ~ is unique.

Because of the severity of heavy snowfall and accumulation of ice and snow, the resulting ice damming problems keep us extremely busy. During these situations, additional roofers are hired and efforts are made to solve as many roofing problems as quickly and efficiently as possible.

For the safety of our roofers, it is necessary to send two roofers on all ice and snow removal and repair calls. Safety is always one of the highest priorities at Korellis Roofing.

Several years ago, we installed new asphalt shingles. The roof now has streaks that extend from the ridge to the eave, with the heaviest discoloration at the downslope edge. What causes this? Based on what was briefly described, this black or dark green streaking on asphalt shingles most likely is caused by airborne algae called Gloeocapsa. It tends to grow in warm, humid environ-ments, such as the South and Midwest, but can occur throughout most of the United States and parts of Canada.

The algae is carried by the wind and eventually comes to rest and grow on shingles. The growth is most noticeable on lighter colored shingles, especially white and off-white.

It is important to recognize that the algae growth is not a performance problem of the asphalt shingle roof system but an aesthetic one that should not cause concern about shingle failure. It generally is not necessary to remove and replace asphalt shingles strictly because of algae growth and the associated discoloration.

If cleaning the algae from the shingles is desired, NRCA does not recommend pressure- or power-washing or using solutions with high concentrations of bleach - these can cause damage. A bleach-based cleaner may prematurely age asphalt shingles, and over-scrubbing or power-washing can remove granules, reducing useful service life. The bleach solution also can harm near-by plants and etch window frames. Additionally, safety is a concern; shingles can become slippery when wet.

If the roof's appearance is not acceptable, and cleaning is the preferred method to improve it, asphalt shingles should be washed with a mild solution of chlorine bleach and water or mild detergent gently applied with a sponge or hand-held sprayer. The surface then must be rinsed thoroughly with water. Unfortunately, cleaning the roof system's surface is only a temporary solution; the algae are likely to reappear.

It is also recognized that metal (galvanized or copper) fixtures (e.g., exhaust fans, flashings) retard algae growth. The water running over the metal creates various compounds that coat the shingles' top surfaces and slow the algae growth.

Installing zinc or copper strips at the ridge is another method for controlling algae growth, but they might not be effective across the entire roof area (because of high concentrations of zinc or copper at the ridge and subsequent smaller amounts of zinc or copper further down the roof). Installation of multiple strips can be a more effective solution. The strips can be incorporated into existing residential roof systems in conjunction with the previously described cleaning methods.

Algae growth is not limited to asphalt shingles. It has been reported on all roof system types, including wood shakes and shingles and concrete and clay tiles.