What All Homeowners Should Know About Ice Dams

ice dams

Every winter, countless homes are plagued by ice dams. Heavy snow and poor roof ventilation bring about a serious problem for homeowners. In this guide, we’ll discuss what ice dams are, how they form, how they can be prevented, and more. 

In this guide, we'll discuss...

What are ice dams?

An ice dam is a blockade of ice that forms at the edge of a roof and prevents melting snow from properly draining off the roof.

During periods of repeat freezing and thawing, water gets trapped under the ice and can work its way beneath roofing materials. This can result in severe moisture damage. The lower the pitch of the roof, the higher the risk. 

Ice dams are one of the leading causes of roof leaks and interior damage. They allow water to leak underneath shingles and permeate housing materials, potentially causing the formation of mold, warped roofing beams, damaged insulation, and more.

Spotting ice dams early will greatly reduce the opportunity for roofing problems. Look for sagging gutters and large clusters of icicles, as each points to the formation of ice dams. 

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How do ice dams form?

Poor ventilation and inadequate temperature control within the attic are the two primary causes of ice dams.

Ice dams form when an excessive amount of warm attic air melts snow on the roof. The melted snow runs towards the roof's edge, and if it's blocked by a ridge of ice, refreezes to form more ice. This cycle repeats itself, creating an ice dam. 

The ice dam cycle involves:

  • Heavy snow falls
  • Heat within the house rises to the attic
  • Roof temperatures become uneven
  • Roofing underlayment is penetrated by water from melting ice

Another contributing factor is poorly maintained gutters. If a homeowner neglected to clean clogged gutters in the fall, melting snow will accumulate in the inferior drainage system and refreeze. A build-up of ice in gutters can collapse the drainage system, or create an excessive weight that forces the roof to sag.

Keep reading about proper gutter care, roof leak procedures, and mold treatment options:

How do I prevent and remove ice dams?

man using roof rake

There are a number of options for preventing and removing ice and snow from a roof

Heated Cables

Heated cables installed along the roof’s edge can effectively combat ice dams.

  • Heated cables equalize the roof’s temperature by heating it from the outside instead of from the inside.
  • This is a great preventative measure, as long as the cables are installed before freezing weather hits.

Roof Rakes

Remove snow from the roof if possible.

  • Use a roof rake or a push broom to carefully pull snow down the slope of the roofline.
  • Avoid pulling snow across the roof, as you could damage the shingles.

Calcium Chloride and Ice Melters

Fill a porous material, like pantyhose, with calcium chloride or another commercial ice melter.

  • Place the bag so it crosses the ice dam and hangs over the gutter.
  • Do what you can to push it into position.
  • The calcium chloride will slowly melt the snow and ice it’s placed over the top of, creating a channel for water to drain off the roof.

A word of caution: Don’t leave these ice melting materials on your roof for an extended period of time. The excess salt runoff can damage grass and plants.

The best practice for decreasing the formation of ice dams is increasing roof ventilation and adding proper attic insulation. An overly warm attic will increase snowmelt and lead to more ice dams.

Keep reading about proper roof ventilation:

How much does it cost to remove snow and ice?

Prices vary depending on your preferred method of removal (and if you plan on doing the removal yourself).

Below, is a list of the average prices for equipment needed to perform a DIY ice dam, as well as the average cost to hire a professional.

Equipment / Material Average Cost
Roof rakes $60 - $180
Heat cables $75 per 100-foot cable
Professionally installed heating cables $22 per linear foot
Professional removal $175 - $250 per hour
While professional service is expensive, climbing around on a snow-covered roof is a dangerous activity. We advise paying for a professional to remove large amounts of snow and ice.

How do I find the right contractor?

Removing snow and ice from a roof is a dangerous practice. That's why we recommend hiring a professional contractor with experience removing snow and ice dams.

An experienced contractor will be able to successfully remove the ice dam and propose tangible solutions to prevent it from forming again.

Before you choose a contractor, ask specific questions about their experience, the equipment they use, and for proof of insurance. 

Hometown Roofing Contractors is one of the easiest ways to find the best local roofing contractor for the job. You can read company profiles, see what other customers have to say about their services, and request quotes from as many roofers as you want.