The function of a snow guard is to prevent snow or ice from causing an avalanche off the roof. Which could cause it to land onto landscaping or pedestrians below. The guard allows the snow to stay on the roof until it gradually melts off. The snow can bond together in wet snow conditions allowing a portion of snow to remain hanging from a roof. The snow will then freeze overnight. The thawing beneath the roof will then cause the entire sheet of snow or ice to slide off the roof.
What Is A Snow Guard And Do They Work?
Typically, homes or businesses with extremely steep roofs or roofs made of slate, wood or metal benefit from snow guards. Those with asphalt shingles typically do not need snow guards.
Choosing the type of snow guard depends on the type of roof that is on the home or business. Aluminum is a favorable material in gutter installations because it has a low corrosiveness and is environmental friendly. Metal roofs come in various metallic options including aluminum, copper and steel. Using the same metal material for the snow guards that is used for the roof will prevent corrosion altogether.
When competing metal materials are used in construction, an electrolyte bridge will form as water flows across the alloys. An excerpt from Metal Roof Snow Guards details what happens in the galvanic process.
“During evaporation water becomes concentrated and water films become more conductive, causing the initially benign water to create a dynamic galvanic effect which causes rust. This phenomenon normally begins to occur when water gets trapped in a crevice, such as under a screw or between the base of a metal guard and the metal roof. Even water lying against the face of the metal guard and the metal roof for an extended period time can initiate the deterioration process.”
Their suggestion is to use a plastic snow guard to retain strength over the colder winter months. They state it is more aesthetically pleasing. They point out how corrosion is especially concerning near coastal areas where salty air can enhance the galvanic process and weaken the guard. In our opinion however, copper would be better choice for roofing, gutter and snow guard material in this type of environment. See our previous blog topic to see the abilities that copper has over other materials.
What will determine whether a residential home or business will require snow guards is the roofing material. Lots of businesses use metal roofs due to the longevity of the material. There are some environmental benefits to using aluminum or stainless steel as a roofing material. See our blog on green guttering and how the choices effect the surrounding environment. If gutters are installed on a roof using metal or granite shingles, it is recommended to get snow guards installed. The gutters will act as a catch for the snow and ice, compounding the problem more.
When it comes to choosing a snow guard, it appears longevity of the guard and safety are a concern. Although we do not install snow guards, we do have another suggestion that will work even better than snow guards where a gutter system has been installed.
Leaf guards can act as a snow guard as well. To accomplish this, a specific type of gutter guard will need to be installed. The guard allows a heat tape to run through the guard melting the snow and ice. This keeps the gutter system functioning as it should. By adding heat tape to the first couple feet of a roof, the snow will not overwhelm the gutter guard. Another possibility is to have the snow removed from the roof.