Ice Dam Prevention

What causes ice dams?

A complex interaction among the heat loss from a house, snow cover, and outside temperatures leads to ice dam formation. For ice dams to form there must be snow on the roof, and, at the same time, higher portions of the roof’s outside surface must be above 32°F while lower surfaces are below 32°F. For a portion of the roof to be below 32°F, outside temperatures must also be below 32°F. When we say temperatures above or below 32°F, we mean about average temperature over sustained periods.

The snow on a roof surface that is above 32°F will melt. As water flows down the roof it reaches the roof portion below 32°F and freezes. Voila! – An ice dam.

The dam grows as it is fed by the melting snow above. It will limit itself to the portions of the roof that are, on average, below 32°F. So the water above backs up behind the ice dam and remains a liquid. This water finds cracks and openings in the exterior roof covering and flows into the attic space. From the attic, it could flow into exterior walls or through the ceiling insulation and stain the ceiling finish.

No uniform roof surface temperatures lead to ice dams.

Ice Dams: Fact vs. Fiction

There is a lot of misinformation out there on the topic of ice dams. This will be the single definitive source for all things relating to ice dams. Towards that end, here are some common misconceptions about ice dams, roof snow, roof ice, and gutter ice removal.

Fact: Ice dams can occur with virtually no snow on your roof.

It’s a question of ice accumulation. It takes very little actual moisture to form ice dams. Even a dusting of snow can create a problem. Of course, it is most often the case that thick snow accumulations create ice dams more quickly.

Fiction: Gutters have something to do with ice dams.

Gutters have nothing whatsoever to do with ice dams. If your home is prone to ice dams you will get them either way. If you have gutters they will fill with ice and provide a foundation for the ice dam above. If you don’t have gutters, the ice dam builds on the cold edge of the roof. We provide ice dam removal for many homes that do not have gutters.

Fact: Gutter systems can be damaged by gutter ice.

We see it every year. A section of otherwise fine gutter is on the ground or hanging precipitously off the edge, filled with ice. Fresh water ice weighs about 60 pounds per cubic foot and gutters are not designed to tolerate that load. It’s important to initiate gutter ice removal sooner rather than later.

Fiction: When it comes to insulation, the more the better.

Improperly insulated homes are just as bad as under-insulated homes when faced with ice dams. We have fixed countless bad insulation jobs for this reason. Specifically, we frequently find insulation done in such a way as to inhibit proper ventilation. If you don’t address air leakage into the attic or rafter spaces, all the insulation you add won’t prevent ice dams.

Fact: You can see ice dams from the ground.

Not always. Indeed, you can usually spot a monster very easily. You can see the two-foot icicles and the little glacier on your gutter. The sneaky ones are above skylights or in roof pan areas far out of sight. Sometimes ice dams grow up valleys and on top of dormers making it almost impossible to identify from the ground.

Fiction: Salt socks are a smart way to address ice dams.

People use pantyhose, old socks, and store-bought cloth tubes filled with ice-melting compounds for removing ice dams. Corrosive substances like rock salt, sodium chloride, calcium chloride, magnesium chloride, etc melt channels through their ice dams. Some compounds are better than others, but all present risks you should keep in mind. Some of these chemicals affect the integrity or color of your roof, some are corrosive to the aluminum when gutter ice is removed this way, some are corrosive to valley metal and other flashings, and some damage plant life as the water drains below. You are rolling the dice when you go this route so be aware.

Fact: Ice should be removed by steam.

Here is the skinny. We are roofers and have fixed hundreds of roofs damaged by well-intentioned professionals with hammers, picks, and hatchets in their pursuit of removing ice dams to help their clients. The damage caused by the less-than-professional souls is almost funny if it wasn’t so serious. In our years we have seen jobs with picks and hammers where removing ice dams was done successfully. It gets down to a question of risk management. We strongly advise against the hack-a-teer approach even if it is cheaper. Roof Ice and Gutter Ice should always be removed with steam.

Fiction: Ice dams need to be thick to cause a problem.

Ice dams as thin as one inch can cause big problems. A good general rule is that the steeper your roof, the thicker the ice dam has to be to cause problems. On lower pitched roofs even a thin ice dam can hurt.

Fact: The leaking caused by ice dams may not show up immediately.

It would be nice if water stains or mold manifested immediately upon entering your home but it simply does not work that way. Often the water that ice dams push into homes travels around wall and ceiling cavities, trapped by vapor barriers and other materials until it finds the path of least resistance to escape. When you discover water inside, it’s usually been there for a while.

Ice Dams Solution

RQ Fabrication installs Perfectly Clear ice dam prevention systems. Call us at 508-829-8989 or contact us to request a quote and learn more. We are licensed and fully insured. All our work is guaranteed. Credit cards are accepted and financing is available.