Solutions to Prevent Ice Dams

Icicles are dangerous not only to people when they fall, but to your home when water gets inside. Icicles are a warning of  ice damming caused by snow melting on your roof. The biggest problem is the water that gets trapped on your roof behind the ice dam. This water is likely to find it's way into your home where it can cause extensive problems.

When you have a roof leak caused by ice dams, you've got to repair the roof and the interior damage to insulation, ceilings and walls. Preventing the formation of ice dams is the best solution to protect your home. You will save time and stress, and ultimately the money invested in a good ice melt solution will be cheaper than multiple repairs. 

This article focuses on solutions you can implement to prevent the formation of ice dams on your roof. It is the third and final article in the series on ice dams which affect all homes, not just older homes with inadequate insulation.

• Ice Dams: Why They Happen & Why You Don't Want Them
• Pantyhose a Quick Fix to Melt Ice Dams
• Preventing Ice Dam Problems … this article!

Insulation Reduces Heat Loss from Living Space

Adding more insulation to an unfinished attic is one of the most popular solutions to reduce heat loss. Insulation slows the movement of air between spaces with different temperatures (read How Cold (Warm) is Your Home?). While most people focus on the large floor area, other places where warm air can flow into the attic include light fixtures in the ceiling, air ducts where they enter/leave the attic, plumbing pipes, electrical wires, chimneys, etc. Attic stairs are another example of potential heat loss unless they are insulated with weatherstripping to fill the gaps around the door when closed.

Ventilation Removes Warm from the Attic

Warm air will ultimately reach your attic so in addition to insulation, you need ventilation in your attic to remove the warm air and the moisture that warm air holds. Ventilation requires a system with:

• Vents to bring outside air into the attic are typically soffit vents underneath the roof overhang along the length of a house. A common problem occurs when insulation blocks these vents and stops air from circulating through the attic.
• Vents closer to the top of the roof allow attic air to leave the house. Gable vents are more familiar because you see them on the sides of houses but ridge vents at the peak of the roof have been the standard for many years with the Building Officials and Code Administators (BOCA) adopting ridge vent requirements for replacement roofs in 1999.

When your home is properly insulated and you have adequate ventilation, you are saving energy and reducing the risk of ice dams. The important word here is “reducing” as there will always be heat loss that reaches your roof. The roof over heating living space will be warmer than the roof immediately above the roof overhang … and that is where ice dams form.

Roofing Materials to Reduce Water Leaks

Between the plywood sheathing that forms the base of your roof and the roofing materials that go on top (the shingles or tile you see),  is a layer of ice and water sealant to prevent water from reaching the plywood or worse, leaking down into your home. Many contractors use a high quality sealant like Grace's Ice and Water Shield product but only for the bottom 3 feet of the roof. When building a home or replacing your roof, you should consider running this product up the entire roof … a common practice on the seacoast.

Solutions to Eliminate Ice Dams

The most common places on your roof to find ice dams are the overhangs and in valleys which commonly get uneven sunlight. There are several solutions available to reduce ice dams and resulting problems when you have excessively large snowfall.

	This home has significant ice dam buildup along the entire edge of the roof, extending up 4 to 6 inches (what's visible here). The ice dam and icicles will grow larger until channels are created to let melting snow drain off the roof. It's also a good idea to rake off several feet of snow to allow sunlight to melt the ice dam faster.
	For many years, heat tape has been used to deliver low levels of heat to roofs to reduce/eliminate the formation of ice dams. Heat tape is an electrified cable, typically laid out in a zig zag pattern along the edge of the roof  and in the gutters. As you can see here, there are still icicles although they're not continuous. The heat tape appears to be creating channels for much of the water to reach the edge of the roof  but some of the water is still freezing.
	The Roof Ice Melt system shown here takes the concept behind heat tape to a new level. The product is made from copper or painted aluminum (30+ colors) to conduct heat from its electrical cables through the entire metal package to reduce the formation of ice dams. Advantages include cables protected from the elements for longer wear, aesthetically more attractive and the system comes with a thermostat that controls when the system turns on and off.
	Metal roofs are an excellent solution in areas that get significant snowfall. Metal roofs shed snow easily and it's common to use different types of brackets, guards or a snow fence to slow the falling snow and break it into smaller pieces, i.e. to avoid an avalanche type accident.