Snow Guards: What Works What Does Not

Do Snow Guards Really Work on Metal Roofs?

Snow guards are effective on metal roofs, but only when they are correctly spaced and installed across the entire roof. Most failures occur because installers use too few guards, place them only at the eave, or use them on a roof panel that is not compatible with the snow retention system. This page explains which snow guard approaches work, which ones fail, and why proper layout and load distribution matter more than the snow guard type itself.

What Works vs. What Fails With Snow Guards

What Works	What Fails
Staggered rows across the roof	Rows placed in a straight line
Proper snow guard spacing based on roof length and pitch	Guessing quantity or spacing
Properly designed & tested snow guards	Untested Snow guard designs
Full roof snow load distribution	Concentrated guards in one area

Common Causes of Snow Guard Failure

Failure Cause	Why It Fails
Too few snow guards	Snow load exceeds holding capacity
No snow guards on upper roofs	Upper roof snows slide off onto bottom roof
Incorrect spacing	Uneven load transfer causes pull-off
Ignoring roof pitch and snow load	Forces exceed design limits

Snow Guard Layout Performance Comparison

Layout Type	Performance	Why
Full-coverage staggered rows	Consistently performs best	Evenly distributes snow loads
Multiple straight rows	Sometimes acceptable	Better than one row, less efficient
Single inline eave row	Fails most of the time	Subjects snow guards to impact

Snow Guard Myths vs. Facts

Myth	Fact
One row of snow guards is adequate on a steep roof	Steep roofs usually require multiple rows to properly distribute snow loads
Snow guards stop all snow from sliding	Snow guards mitigate snow movement; they do not stop melting or shedding of small pieces
Bigger or stronger snow guards mean fewer are needed	Proper quantity and spacing matter more than individual snow guard size
Isolated snow guards will protect a doorway or vent pipe	Unbalanced snow loading on the snow retention system may cause attachment failure
Snow guard failures are caused by poor designs	Most failures result from improper layout, spacing, or installation methods

Why Snow Guards Fail on Metal Roofs

Snow guards can fail on metal roofs for various reasons, including poor design, incorrect installation, or mismatched systems. Common causes of snow guard failure include installing too few snow guards, placing them only at the eave, neglecting the importance of roof pitch, and exceeding the rated capacity of the snow retention system. By understanding the most common reasons snow guards fail on metal roofing, property owners and contractors can select the appropriate snow retention system on the panels used for the project, proper spacing patterns, and the right attachment method for optimal long-term performance.

Improper Contractor Planning

The absence of snow guards is not an option in this situation. Here is a recently constructed building, where the contractor did not install snow retention. The business owner may be responsible for personal injury or property damage caused by snow and ice falling from the roof. There is an entryway and a parking lot right underneath, where people can park before entering the business. The correct way to install snow guards on this roof is to address the upper roof first so the snow and ice do not fall onto the lower roof. Snow guards should also be installed on the lower roof to keep the snow and ice from sliding off.

Wrong Spacing and Layout Pattern

Spacing of snow guards on a roof is an essential aspect of a snow retention system. Pad-style and seam-mounted individual snow guards should not be placed in straight lines (As shown in the picture). Install snow guards on every panel flat and never skip space between the seams as pictured. Many companies will quote an insufficient amount of snow guards for a particular job to be the lowest bidder. The result is a loss of money due to a misapplication caused by an inadequate layout destined to fail. The snow guards in this image are bending and will flatten out over time, rendering them useless.

Wrong Type of Snow Guard

A properly designed snow guard has a flat face at the front of the base at least 3 inches wide. If it doesn't have a wide enough face, it acts as a snow breaker instead of a snow retention, which is not ideal for this application. The guards in this picture have a 1.5-inch-wide face placed near the back of the base. This design allows snow and ice to pass through the guard. As you can see in the picture, the guards offer very little protection against sliding snow and ice. A worker climbed onto the roof to manually remove snow.

Isolating Snow Guards Over Doors

The leading cause of failure is isolating snow guards! If snow guards are installed only above doorways or in other isolated areas, the attachment may become overloaded and come off. Snow and ice freeze together, usually across the entire roof. When this occurs, the snow retention system becomes trapped in the frozen mass. When the snow and ice begin to melt, it will not separate easily from the isolated area of snow guards. The result is an unbalanced snow load placed on the isolated section of snow guards. The snow retention system will most likely fail in this case.

Snow Load Miscalculation

People often guess what the snow load is for the project instead of doing the actual research. We base all our snow guard recommendations on the ground snow load rating for the geographical area. Based on historical measurements from weather stations across the United States, ground snow loads are useful for designing a snow retention system. It takes neither the structure's attributes nor its purpose into account. If you're not sure what your ground snow load may be, call your local building code enforcement office.

Snow Rails Clustered at Bottom Edge

The placement of snow guards is NOT a mixture of art and science as some manufacturers have claimed. The best spacing guideline is to spread the snow load across the entire roof to keep all the snow and ice from moving initially. Never place snow rails solely on the lower half of the roof plane unless the roof plane is short from ridge to eave. (See Photo) Never run pad-style snow guards in a single line; always use multiple rows up the roof to spread the load evenly. Following this rule will prevent the initial shifting of snow and ice on a roof, which can destroy the snow retention system, as shown in this photo.

Cheap Seam-Mounted Cast Guards

Seam-mounted snow guards can be mounted any time of year and are usually quick and easy to install. They do, however, sit up on the high seam, which can leave unprotected areas on wider panel flats. This flaw can result in seam damage when snow and ice slide past the snow guards and catch the outer edges, as shown in this picture. The SnoCleat RC product addresses this issue by providing a swivel base that rotates upon impact from sliding snow and ice. A seam-mounted snow bar with IceStoppers is always a better alternative.

Mid -Face Snow Guard Design

Mid-Face Snow Guard designs may provide a point of leverage to pry the front of the guard up. The face of a snow guard should always be located at its furthest forward point, creating a leverage point that transfers the load to the lower, downhill section of the base. The snow load applied to a snow guard with a mid-face may pry the front of the guard upwards. Water could become trapped beneath the guard, and the attachment can fail when the trapped, frozen water expands.

What Makes Snow Guards Actually Work

It is best to identify your metal roof type before choosing a snow retention system. Attachment methods vary by roof style and can affect performance and roof warranties. Exposed-fastener (screw-down) metal roofs can support mechanically fastened snow guards or snow rails, but some property owners prefer to avoid drilling new holes. In those cases, adhesive-mounted polycarbonate snow guards are a practical alternative. Standing seam metal roofs should never use screw-mounted snow retention because screw penetrations may restrict panel movement and void the roof warranty. The most common snow retention options for metal roofs include screw-down snow guards and rails for exposed-fastener panels, seam-mounted clamp-on snow guards and rails for standing seam systems, and adhesive-mounted polycarbonate snow guards for a non-penetrating installation.

Seam Mounted Snow Bars

A seam‑mounted snow guard system that uses low‑torque cup‑tip set screws installs easily in any season. If properly designed, seam-mounted snow bars can withstand heavier snow loads. A clamp-on snow retention system has no release factor so make sure the system is spaced properly by following the manufacturers spacing guidelines. Snow Rails are also available as a screw down version for exposed fastener metal roofs. It is strongly advised to obtain a price quote and layout recommendation before placing an order. See the spacing recommendations for SnoBar and ColorBar

Adhesive Mounted Snow Guards

The adhesive mounted SnowBreaker shown in the picture is the only model designed to operate in straight lines, as it aims to break up the snow and ice rather than stop it. Adhesive-mounted snow guards have a significant advantage over seam-mounted or mechanically fastened guards in terms of long-term roof integrity. If they become overloaded, they will release without damaging the roof panel. When the weather permits, they can be reinstalled in the same locations on the roof. Adhesive-mounted snow guards do have a substantial cure time in warmer weather and sometimes require more guards to do the same job as a snow rail.

Screw-Fastened IceStoppers

IceStoppers prevent snow and ice from sliding under the SnoBar and ColorBar. They should be mounted perpendicular to the roof panel and have a 90-degree foot on the bottom to keep them from bending under the bar. Our IceStoppers are mechanically attached to the bar with self-drilling tek screws to prevent them from flipping up in the wind. Buyer beware: some poorly designed snow rail systems on the market feature curved snow-stopping clips that slide onto a round channel on the bar. Because the clips are free-floating and not attached to the bar, wind can lift them and swivel them upward in high gusts.

Staggered Pattern of Snow Guards

The proper way to prevent snow slides on a sloped metal roof is to evenly distribute the snow load. It is necessary to place pad-style snow stops across the entire roof surface, in a staggered pattern. The first pattern should consist of two rows of staggered snow guards at the eave. This image shows how a staggered pattern of snow guards essentially acts as fingers to keep snow and ice in place. Depending on the roof pitch and panel length, patterns of snow guards may need to be equally spaced going up the roof. Always refer to the spacing guideline page for proper spacing.

Multiple Rows of Snow Retention

Roof pitch, ridge‑to‑eave distance, panel‑flat width, and ground snow load rating determine the recommended number of snow‑guard rows. The best way to retain snow and ice on a roof is to evenly place multiple rows of snow retention spaced up the roof to minimize the chance of movement. Unevenly distributed snow loads can trigger avalanches that may destroy anything in their path, especially when the lower edge of the roof lacks adequate snow retention. This picture illustrates a properly installed SnoBar system on a large project in Colorado.

Upper Roofs Before Lower Roofs

One of the quickest ways to compromise your snow retention system is to allow snow and ice to slide from an upper roof down onto a lower roof. Before installing snow guards on lower roofs, make sure to install them on upper roofs first. If snow and ice slide off an upper roof onto a lower roof, the resulting impact force and added snow load can lead to premature failure of the snow retention system. This error is often overlooked and is a common mistake when installing snow rails and individual guards.

Vent Pipe and Chimney Snow Guards

One of the most frequently asked questions is, Will snow guards protect chimneys and vent pipes? The short answer is yes, but only when the snow‑retention system spans the entire roof rather than sitting only above a pipe or chimney. That's why we offer VentSaver models specifically designed for this purpose. The patented fin on the VentSaver products splits the snow and ice around the pipe. As a bonus, all VentSaver models include a stainless-steel strap that helps support the vent pipe or chimney. The VentSaver works alongside snow guards or replaces them entirely to protect vent pipes and chimneys.

Snow Guards: What Works and What Doesn't (FAQs)

What actually works when installing snow guards?

Snow guards work when they are properly selected, correctly spaced, and installed properly across the entire roof. Systems that distribute snow loads evenly across the whole roof surface consistently perform better than isolated or single-row installations.

What is the most common failure with screw-down snow guards?

Screw-down snow guards should only be installed on exposed-fastener metal roofing. Never screw snow guards into a standing seam panel. Follow the recommended installation methods to secure mechanically fastened snow retention systems properly.

Why does snow guard spacing matter so much?

Proper spacing allows snow loads to be distributed evenly across the entire roof, not just over doorways and ventpipes. Spacing snow guards too far apart and isolating them can overload the guards and increase the risk of failure.

What does not work when installing snow guards?

Snow guard failures often occur due to improper installation techniques. Problems with a project usually arise when clustering guards above doorways and vent pipes, when ignoring spacing guidelines, and when exceeding the roof snow-load limits of the snow retention device.

Do snow guards fail because of the product or the installation?

Most snow guard failures result from misinstallation and ignoring layout recommendations, rather than from defects in the guards themselves. The most common failures result from improper spacing, inadequate placement, and not taking the roof pitch and snow load into consideration.