Ice dams are common in the winter when the temperature dips and snow starts falling. Despite the wide variety in roofing and home styles, ice dams are inevitable when you pair a roof and gutter with frigid temperatures. But what exactly is an ice dam, and can you prevent them?
What is an Ice Dam?
According to the University of Minnesota, the definition of an ice dam is “a ridge of ice that forms at the edge of a roof and prevents melting snow (water) from draining off the roof.” As this water builds up on the roof with nowhere to go, it may eventually leak into the interior of your property, damaging walls, ceilings, floors , insulation, and more.
Why Do Ice Dams Occur?
Ice dams happen due to non-uniform roof temperature. Specifically, the following “ingredients” are needed to make one happen:
- Snow must form on a roof.
- Higher parts of the roof temperature must exceed 32º Fahrenheit (0º Celsius).
- Lower parts of the roof must be lower than 32º Fahrenheit (0º Celsius).
This means the temperature outside must be below freezing.
Once the snow at the top of the roof melts (since it is above freezing temperature), the water runs down the roof, reaching the portion of the roof that is below freezing. When the water freezes, it forms an ice dam.
The dam is “fed” by the melting snow above; this water backs up behind the ice dam, caught in the area that is above freezing temperature. Because it is too warm to freeze, the liquid builds up with nowhere to go.
How do Ice Dams Affect Properties?
Ice dams can have a significant impact on a roof and internal property. Effects can include:
- Water damage .
- As water backs up on the roof behind the freezing point, it can slip through cracks and openings, go under shingles, drip into the attic, and travel through ceiling insulation.
- Stained ceiling finish.
- Damaged contents.
- Roof failure from the weight of snow.
Ice Dam Prevention
The good news is, there are steps you can take to help prevent ice dams, and even mitigate damage if they still form. The National Weather Service offers the following tips to prevent ice dams :
- During winter, make sure gutters and downspouts are regularly cleared of snow, and safely remove any icicles when you see them.
- Remove debris, including sticks and leaves, from gutters and downspouts (this helps provide passage to melting roof snow).
- If possible, reduce the amount of snow on your roof to a minimum, helping to prevent ice dam formation.
- Consider investing in “roof rakes,” which are long-handled devices that let you stand on the ground and “tow” snow off the roof, avoiding the danger of climbing up top.
- Go into your attic to evaluate ventilation and insulation. Generally, professionals indicate the R-value of attic insulation should be at least R-30. (Keep in mind, R-38 is ideal in northern climates.)
- Consider reaching out to a roofing or insulation contractor to ask about improving airflow under your eaves or soffit area, along the underside of the roof, and out through roof vents. Good insulation helps to prevent heat loss inside the property. Furthermore, properly venting air in the attic helps to ensure it remains cold enough to prevent or at least help minimize the freeze/thaw cycle on the roof.
- Water Removal. Once a plan is determined, water extraction begins using powerful extraction units and pumps.
- Damaged Material Removal. In the fourth step, technicians will let you know if any items cannot be restored. These items will then be removed as soon as possible to help expedite the drying process.
- Cleaning, Sanitizing, and Deodorization. A variety of products, equipment, and specialized techniques are employed to help clean, sanitize, and remove odor from furniture and other belongings.
- Drying. Industry-leading drying equipment is used at this stage to help remove water you can’t see (like moisture within materials). This helps return items to their standard moisture level, after most of the water has already been removed.
- Generally, drying equipment is placed when technicians arrive for the first time, though the amount and type of equipment can vary depending on the job.
- Repairs and Construction. In the final step, any last needs are met, including construction, if necessary. Sometimes, the damage requires rebuilding after cleanup and restoration takes place.
For more information, please visit our FAQ and Glossary .
Sources:
https://extension.umn.edu/protecting-home-rain-and-ice/dealing-and-preventing-ice-dams