Ice damming is becoming an increasing problem as freeze/thaw cycles have become more common throughout the winter. As a child I remember it getting cold in the fall and thawing in the spring. Now it is common to see several freezes and thaws in just one month. This can cause major problems.
To understand the problem of ice damming you must understand what causes it. Ice damming is essentially a pile up of ice which typically starts as ice melts off of a warm roof and runs down the roof until it refreezes in either a cold portion of the roof or a cold gutter. As the water continues to run down, the ice builds up on the cold gutter area and the part of the roof that overhangs the walls of your home (above the soffit).
Many people make the mistake of taking a hammer, hatchet or axe to their gutters. Some will throw salt on their roof hoping to melt the ice dam. There couldn’t be worse solutions than this. If you’re looking for a quick fix, fill a nylon stocking with calcium (which is non-corrosive) and place it across the gutter vertically with the top hanging down. This will create a gate for the water to flow down…. still, it is only a temporary quick fix.
So what is the solution? You want your roof to stay cold and only melt the snow and ice in the spring. That way when water starts to melt in the spring it will continue into your gutters and spill out of your downspouts. This is achieved by having adequate ventilation in your attic so that your roof stays cold. You want to create a climate envelope to keep you warm, but keep your roof cold. This is achieved by having adequate insulation above your drywall ceiling but below your roof AND by assuring that your attic space is ventilated so cold air from outside can access your attic space.
There are several steps you’ll want to take to fix these problems if you choose to fix the problem the right way.
1) Make sure you have adequate soffit ventilation. This is needed to provide a source of cool air that can be drawn up into the higher vents in your attic.
2) Make sure you have adequate roof vents. Most ridge vents will give you more than adequate ventilation.
3) Vent chutes will provide the necessary bridge between the vented soffit overhang and the area above attic insulation. This keeps the insulation away the roof decking and allowing the decking to remain cool. At the same time, this allows for the cool air from the soffit to be drawn up to the attic vents.
4) Attic insulation, up to the recommended R-60 in Wisconsin, will keep warm air from inside of your home from warming your roof decking and melting the snow on the roof.
When you replace your roof, install two layers of ice and water dam (5 1/2 feet) shield.
Take these steps and you’ll avoid damage to your gutters, ceilings and drywall.