What snow guards do
A snow guard is a device or system fastened to the roof that holds the snowpack in place. The goal is not to keep snow on the roof forever, but to let it leave gradually, by melting or sliding off in small amounts, instead of all at once. Angi’s overview of snow guards describes the main reasons homeowners install them: protecting people and property below the roof edge, and protecting roof elements such as gutters, vents and flues from the force of sliding snow.
The weight involved is significant. A large roof section can shed many hundreds or thousands of pounds of snow in a single slide. That load can rip a gutter and its hangers off the fascia, bend downspouts, break shrubs, damage cars and injure people at entries and walkways.
Why metal roofs need them most
Metal roofs are smooth and shed snow quickly. That is one of their advantages, but it means snow can let go suddenly, especially on sunny days after a storm or when the roof warms from below. Snow retention is commonly recommended for metal roofs in snow country, and many roofing manufacturers offer systems designed for their panels. Steep slate, tile and some asphalt shingle roofs over entries and walkways also benefit. See gutters for metal roofs.
Types of snow guards
Pad-style guards
Individual cleats or pads fastened to the roof in a staggered pattern across the lower part of the roof. They break up the snowpack and hold it in place. Common on shingle, slate and some metal roofs.
Rail or bar systems
Continuous bars or pipes clamped to the seams of standing-seam metal roofs, often in one or more rows parallel to the eave. They provide strong retention without penetrating the metal panels when installed with seam clamps.
Fence-style systems
Larger rail systems with multiple bars or mesh, used on steep or very snowy roofs and on commercial buildings.
Which type fits depends on the roof material, slope, snow load and the building’s exposure. Manufacturers publish layout guides; for large or steep roofs, an engineered layout is common.
Where they go
Snow guards are usually placed in the lower part of the roof, above the exterior wall line, so the snow they hold sits over the house rather than over the gutter. Additional rows may be placed higher on long roofs. Areas above entries, walkways, decks, driveways and lower roofs get priority. On roofs where valleys or dormers create concentrated slides, guards are placed to break those up too.
How they protect gutters
Gutters on snowy roofs face two threats: the slow weight of snow and ice, and the sudden force of sliding snow. Snow guards address the second. With the snowpack held back, the gutter sees meltwater instead of a sheet of snow and ice. Gutters still need strong attachment: hidden hangers at close spacing into the rafter tails and heavier-gauge material. See snow load and gutters and gutter hangers explained.
Snow guards and ice dams
Holding snow on the roof longer can, in some homes, contribute to ice at the eaves if the attic loses heat. That is not a reason to skip snow guards where people and property are at risk, but it is a reason to address attic air sealing and insulation at the same time. Heat cables can keep a drainage path open in problem areas. See ice dams and gutters and heat cables for gutters.
Gutter position on snow-shedding roofs
On roofs where snow does slide, gutters are often mounted slightly lower, so that a line extending the roof plane passes just above the front lip. Sliding snow then passes over the gutter rather than hitting it. A drip edge or gutter apron keeps water from running behind the gutter at this lower position. Combined with snow guards, this gives gutters the best chance of surviving winter. See drip edge and gutter apron.
Installation and roof warranties
Snow guards must be attached in a way that does not cause leaks or void the roof warranty. On standing-seam metal roofs, clamp-on systems avoid penetrating the panels. On shingle and slate roofs, guards are installed under or through the roofing with proper sealing, ideally when the roof is installed. Ask the roofer or the roofing manufacturer which systems are approved. Retrofitting guards to an existing roof is common but should be done by someone familiar with that roof type.
Maintenance
Snow guards need little maintenance, but they should be checked each fall: loose clamps, bent bars and missing pads reduce their holding power, and debris trapped behind rail systems can hold moisture against the roof. After unusually heavy snow, look for guards that have shifted. If gutters below still get damaged, the layout may need additional rows or a different system.
When to consider snow guards
- Metal roofs in areas with regular snowfall
- Roofs over entries, walkways, decks, driveways and parking
- Homes where gutters have been torn off by sliding snow
- Lower roofs, skylights or solar panels below a snow-shedding roof
- Vacation homes and cabins where nobody is around to clear snow
Cost and value
Snow guards are usually a small fraction of the cost of a metal roof, and far less than replacing torn-off gutters, damaged landscaping or a car hit by sliding snow, let alone an injury. On a new metal roof in snow country, including snow retention from the start is generally simpler and more reliable than adding it later. On existing roofs, start with the areas over entries and walkways.
Snow guards and solar panels
Snow slides off glass solar panels even faster than off metal. Below arrays, snow guards or snow retention designed for solar protect gutters, lower roofs and people. See gutters and solar panels.
Regions where snow guards matter
Snow guards are common in Colorado’s mountains, Western New York, Minnesota, Wisconsin, Michigan, New England and anywhere metal roofs meet regular snowfall.