It’s that time of year again…Furnaces are cranking. Fireplaces are working overtime. Snow is in the air. You guessed it: it’s Ice Dam Season. And there’s no better place to cultivate an Ice Dam than a Chicago steep-slope roof in winter.
What Is an Ice Dam?
Let’s first look at what an Ice Dam is. Ice dams form when snow melts from the upper portion of a steep-slope roof and then refreezes over the lower portion of the roof. This freeze/thaw cycle happens because the upper sections of the roof are typically warmer than the lower sections (more sun exposure, poor attic ventilation, etc.). What results is the formation of a section of ice that acts like a dam, causing melting snow to build-up underneath the primary roof covering.
So where does this water build-up go? Well, it usually ends up as a nice brown water spot on your ceiling or wall. Score: Chicago winter – 1.
It’s true that we live in a region where today it’s -20°F and the forecast for tomorrow calls for 45°F. Chicago steep-slope roofs are prime real estate for Ice Dams. So, what do you do about it?
Prevent Ice Dams with Ice Barriers
The 2012 International Building Code (IC 2012) calls for an “ice barrier” on all asphalt shingle, metal shingle, mineral-surfaced roll roofing, slate and wood shake and shingle roof systems. The code explains it further by noting that this is required on roof systems that have a history of ice forming along the eaves. The solution outlined in the IBC 2012 is the installation of an ice barrier, at least two layers thick, installed from the eaves to at least 24” inside a building’s exterior wall line. Or, in plain English, ice and water barrier products must be installed on all steep-slope roof applications. Score: Chicago Roofers – 1
There are several different products out there that accomplish this: Owens Corning has its WeatherLock® line; GAF has WeatherWatch®, StormGuard® and UnderRoof2™ as the company’s leak barrier options; Tamko has Moisture Guard Plus®; and others. Each of these products features a self-adhesive, modified asphalt material that acts as a self-sealing waterproof barrier for the most vulnerable areas of the roof. When installed correctly by a Licensed, Professional Roofer as part of a roof system on a properly vented roof, the negative effects of the Chicago freeze/thaw cycle should be minimized. Score: Chicago Roofers – 2.
Most manufacturer’s suggestions for the installation of “ice barriers”: from the eaves, installing a minimum of at least 24” inside a building’s exterior wall line; and in the valleys, installing a minimum of 18” – in both directions – extending out from the center line. These are the two areas most prone to Ice Damming. This coverage is in excess of the requirements of the IBC 2012, but given how frustrating water penetration is for building owners and residents, it seems that this seemingly over-zealous application would be the best means to ensure the improbability of developing an Ice Dam on your roof. Score: Chicago Roofers – 3.
Thanks to the ice barrier products available on the market today, Ice Dams can become a thing of the past. So, although we live in a region where Mother Nature is seen to be indecisive at best, a region where the elements can wreak havoc on people, places and things in their path, Chicago Roofers have won this round. Ice Dam season is gone…here to stay is winter, plain old winter.