5 Causes of Ice Dams and How to Prevent Them

Homeownership is an exciting and eventful adventure of projects, maintenance, and learning. It can seem like there’s always something to fix. Some issues you decide to put off till later, but when it comes to your roof, the problems can’t wait. If the issues get too bad, you might literally not have a roof over your head.

While you may be more concerned with thunderstorms or the high winds taking aim at your shingles this time of year, you should know that roofs in Utah are susceptible to many types of damage, including ice dams. Ice dams are ridges of ice that form along the edge of your roof when melting snow on the roof thaws and refreezes along colder eaves. If not removed, they can damage more than your roof. They can damage the interior of your walls, leaving you with a hefty repair bill.

How to Identify an Ice Dam

If you see a large chunk of ice on the bottom edge of your roof, your investigation is over; you’ve got an ice dam. Despite the winter wonderland-esque appearance of sparkly icicles hanging down the side of your roof, any ice buildup indicates there might be an issue. Well-made roofs will not have hanging ice at all, only a pile of fluffy snow at its edge.

You may also notice signs of a problem inside your home, such as water stains or mold forming on the drywall where the wall meets the roof.

Another place to scope out for issues is inside your kitchen cupboards. The air in your kitchen is usually more moist than other areas in the house, and since cupboards stay closed most of the time, the air can stay still, forming condensation in the back of your cupboards and walls. If you notice this issue, it’s a tell-tale sign of an insulation or thermal bridging problem that can lead to ice dams.

5 Causes of Ice Dams

1. Fluctuating Temperatures

Sometimes, Mother Nature likes to keep us on our toes. Temperatures slightly above freezing during the day and below freezing at night are prime ice dam conditions. In these conditions, it doesn’t matter much how cool or warm your roof is; the snow will melt during the day and refreeze at night. When these conditions persist, it’s only a matter of time before the ice builds up in your valleys, along your overhangs, or other parts of your roof.

If you’re experiencing these conditions, your best defense against ice dams is raking as much snow off your roof as possible. No snow to melt means no snow to refreeze.

2. A Hot Attic

Ice dams can sometimes form on a non-energy-efficient home with an attic that is not well insulated and doesn’t have good ventilation. Poorly insulated areas in the attic, such as light fixtures, outlets, and doors, might allow warm air into the attic.

A large fraction of ice dams form because of a hot attic, which warms the roof, creating ideal conditions for ice dam formation. One way to decrease your chances of getting ice dams is to call experienced Utah roofing contractors for a roof inspection and follow any advice they give about keeping your attic from heating up.

3. Weak Spots in Walls

Homes built before 1960 usually need better insulation, especially where walls meet the roof. Also, homes with roofs with low slopes or short overhangs may have the most insulation issues. Heat transfers through studs and warms the roof deck, melting the snow. That melted snow runs under the snow to the overhang. Because of poor insulation, it quickly cools and freezes again.

4. Radiant Sun Heat

Even if temperatures are frigid and below freezing during the day and night, ice dams can still form if radiant heat from the sunshine melts the snow on the roof. That is out of your control. Radiant heat is not something you can predict. You won’t hear about it on the weather channel; there’s no way to measure it. It just occurs. For this reason, there is no 100% guarantee of avoiding ice dams.

However, the best way to decrease the risk of forming ice dams is to remove all the snow from your roof as frequently as possible.

5. Wind and Sun

Sun and wind are ingredients for a perfect ice dam recipe. Wind may blow snow off your roof, mainly at the ridge, exposing roof materials to the warm sun and melting the snow surrounding it.

Ice Dam Prevention

While some weather circumstances are out of our control, there are some surefire ways to prevent ice dam damage to your roof.

  • Clear Drainage Paths – Your gutters carry snow melt away from your roof and down to the ground. Make sure leaves and other debris are not blocking them.
  • Improve Attic Insulation – A warm attic contributes to the problem by melting the snow above. Adding insulation and sealing gaps between the attic and the house below will help keep the temperature down in the attic.
  • Increase Ventilation – Roof and soffit vents allow hot air out drawing in cooler air from outside. Air circulation in the attic is key to keeping temperatures down.
  • Keep Snowpack Down – The more snow you have on your roof, the greater your chances of developing an ice dam. Raking excess snow from lower portions of the roof can help prevent ice damming.
  • Install Heat Cables – Installed along the edge of your roof, heat cables keep water from refreezing, allowing it to run off in the gutters. Heat cables can be a great solution in areas where heavy snow is common.

Learning all there is to know about home maintenance and roof safety can be like learning a foreign language. It doesn’t happen overnight. Who knew there was much to learn about how ice and snow behave on your roof? Knowledge is power, and now you know all about ice dams on your roof, how they form, how to look out for them, and how to prevent them.

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