As winter hangs on into March for many parts of the U.S., ice dams continue to build up, causing leaks and exasperation. But the puck-sized calcium chloride tablets advocated in this TV news report: "Roof Concerns Lead to Steady Demand For 'Roofmelt'" are not an answer. They might provide a moment of temporary relief, but the corrosive chemical can discolor roofing, eat away at flashings and damage landscaping below. As the Ice Dam Company, a roofing company based in Hopkins, Minn.,puts it in this first rate resource on ice damming : "You are rolling the dice when you go this route."
Preventing problems requires action beforehand. No one knows this better, perhaps, than the engineers at the Cold Regions Research and Engineering Laboratory (part of the Army Corps of Engineers). The report "Minimizing the Adverse Effects of Snow and Ice on Roofs" (PDF), has been around more than a decade, but it remains a steadfast reference for designers and builders on preventing ice damage. If only its conclusions were well reported and common knowledge:
- Ice at roof eaves is minimized when roofs are well insulated and ventilated (and "well-insulated" means that major air leaks through the lid have been stopped before insulation is installed).
- Low-slope roofs that drain to cold eaves are particularly problematic in cold climates. It is better to drain low slope roofs to internal roof drains (unless the low-slope roof is metal).
- Steep-slope and slippery-surfaced sloped roofs need snow guards to prevent damage from falling snow and ice.
Of course, it is necessary to take immediate action on existing problems. The best solution: Use an industrial steamer – a machine that might resemble a pressure-washer, but is not.