Winter is here, and so is the potential for ice dams. Having icicles form after warm weather is one thing, but it becomes a significant issue if these icicles are caused by ice dams. To reduce the potential for damage to your home, the home inspection professionals at HomePro Inspections want you to understand why it’s important to recognize how ice dams form, how they can impact your home, and some methods you can use to prevent them from forming.
An ice dam at the edge of the roof
What is an ice dam?
Icicles can form at the bottom edge of a roofline or on gutters when water gets cold enough to freeze. When water runs down your roof and approaches freezing, the water dripping off the edge begins to form icicles.
As gutters fill with water and freeze, they become heavy and can damage your gutter system. If the water accumulates, it creates an ice dam at the eaves, preventing water from flowing over the roof's edge. This water can seep under the roof coverings and into the eaves and attic, and eventually into the walls and ceilings.
Icicles and ice dams indicate a more significant issue with the house. Ice dams can develop when the roof covering is warmer than the eaves, even in below-freezing temperatures.
What are the primary causes of ice dams?
The two main causes of ice dams are inadequate insulation and insufficient ventilation in the attic. If your home has minimal insulation, heat from inside will rise into the attic and warm the roofing materials. Snow on these surfaces will melt and flow to the edges of your roof. The roof overhangs are colder than the attic space. Once that water reaches the edge, it begins to refreeze and accumulate.
How an ice dam forms
Inadequate ventilation will cause condensation to build up on the bottom of the roof decking. Moisture from inside your home will find its way into the attic space, and condensation on the roof decking and structural materials may cause staining and/or moisture damage.
When we inspect attic spaces during the winter months, we often notice frost on nails and other metal fasteners where ventilation may be insufficient. Upon observing frost, our home inspectors will check for signs of moisture staining and indications of ice dams.
On one home inspection years ago, I saw icicles in the attic space of an older home that had very little attic space ventilation. I took photos and documented the condition in the home inspection report.
How can you prevent ice dams?
Often, resolving this issue is quite straightforward. The most effective way to prevent ice dams is to enhance the insulation and improve ventilation in the attic. If the roof is not warm, any snow that falls on it will not melt readily. Ideally, the roof should be at a temperature similar to the outside air. This prevents snow from melting and refreezing at the eaves. Some older homes do not allow additional insulation where the exterior wall meets the roof's slope. If this is your case, you can try one or more of the following options.
You can sometimes use heating tapes or cables to melt ice dams at the eaves and create pathways for water to flow off the roof. However, using these devices only addresses the symptoms and not the conditions that cause the ice dams. Therefore, your first course of action should be to assess the insulation levels and ventilation in your attic space.
Another preventative measure is using a roof rake to remove fresh snowfall from the eaves of your home. Clearing the snow from the eaves allows sunlight to warm this part of your roof, thereby helping to reduce ice dams. You need to be especially cautious not to damage the roof surface while using a roof rake. However, this method does not address the underlying cause of ice dam formation.
Using a roof rake to prevent ice dams
At HomePro Inspections, our home inspectors are trained to inspect your attic space and identify any defects that may lead to damage. Any issues are documented in your home inspection report and recommended for resolution by a qualified professional.
Visit our website to learn more or to schedule your home inspection in the Rochester, Owatonna, and Faribault, MN, areas. You can also contact us today at (507) 202-8942, send us an email, or use our online “Schedule Now” feature to set up an appointment.