This article describes snow retention systems for smooth-surfaced roofs such as glass roofs, plastic roofs and metal roofs. We describe both glue-on snow guards and the types of clamp-on snow fences for these roof systems.

Details include the glue-on snow guard installation steps, advice about using special adhesives, adhesive curing time & adhesive runout & tooling.

This article series illustrates types of snow guards or snow brakes or other snow retention devices used on metal, rubber, asphalt, and slate roofs and we explain and illustrate in photographs just how and where these devices are attached to building roofs. We give the reasons for snow & ice retainer use and their history.

Metal, Glass, Plastic Roof Snow Retention Systems: Clamp-On & Glue-On Methods

Metal or other smooth-surfaced roof snow guards are often installed by gluing the snow guard to the metal, glass or plastic roof surface in the center of pans between the standing seams. Berger and also SureBond both note that there it may be possible to install successful adhesive applications on other roof surfaces as well. [2]

[Click to enlarge any image] Our photo (left) illustrates a plethora of snow guards fastened to a metal roof on the Vassar College Campus.

It appears that the maintenance department has tried a variety of products on this roof, with mixed success.

Our second photo (below left) shows the same building roof in January 2013, with partial snow cover.

You can see these snow guards at work as they prevent snow and ice on the upper roof slope from sliding down and falling off at the roof eaves.

Glue-Down Snow Guards for Glass, Plastic or Metal Roofs

Step by step details for installing adhesive-type snow brakes or guards on metal, glass, or smooth plastic roofs are at SNOW GUARD GLUE ON INSTALLATION.

Excerpts are below. We agree with opinions encountered among roofers that it's better to glue snow guards to a metal roof (or use device that clamp to the standing seam) for two reasons:

1. Leaks: Even though some snow guards are sold with pre-drilled holes for mechanical fastening of the retaining device to the roof surface, every nail or screw is another hole in the roof, and another potential leak.
2. Thermal damage: Mechanically bonding a flat-bottomed snow guard to a metal roof may result in roof damage, tearing, leaks, connector hole elongation during wide temperature swings on the roof.
   
   Thermal expansion differences between the snow guard itself and the metal roof surface may be substantial. Superbond's SB-190, in contrast, can tolerate significant thermal change without damage.

Because of the problem of poor adhesion of the snow guard to the roof that later come loose or creep down the metal roof, manufacturers offer tips for a successful installation including

• buying the proper quantity of snow guards,
• using the proper adhesive,
• cleaning the roof surface, and
• making sure that weather conditions are right before trying to glue these snow brake devices onto the roof surface.

See SNOW GUARD GLUE ON INSTALLATION for complete glue-on snow guard installation details.

Clamp-On Metal Roof Snow Guards & Brakes

Step by step details for installing clamp-on -type snow brakes or guards on metal, glass, or smooth plastic roofs that include standing seams or similar ridges that serve as a mounting point are at SNOW GUARD CLAMP ON INSTALLATION.

Excerpts are below.

Two types of clamp-on snow brakes & guards are widely used on standing seam metal roofs: individual snow guards that clamp to the roof seam (below left) or horizontal snow brakes that use multiple clamps across the roof surface (below right). Some of these systems can also be adapted for plastic, glass or other smooth surfaced roofs if there are suitable mounting points in the roof structure.

At above left are metal snow guards clamped to the steams of a standing seam metal roof. These snow guards are not installed following the recommendations of some manufacturers who suggest their guards be glued to the pans centered between the standing seams, but this is a quick and easy installation approach.

Metal roofs using long horizontal snow bars or snow brakes (photo at above right) have these snow retention systems installed using clamps on individual standing seams.

Can these snow guard methods be used on other types of roofs? Yes.

• Corrugated metal roofs also accept snow guards, typically made of bronze or galvanized iron and referred to as a Snow Guard Shoe.[1]

• Slate roofs (photos shown earlier in this article series) using long horizontal snow brakes mount the brake or fence on brackets nailed to the roof, with the nailed portion of the mounting bracket extending up under succeeding courses of slates to avoid risk of leaks around mounting bolts.

See SNOW GUARD CLAMP ON INSTALLATION for complete clamp-on mechanically-attached on snow guard & snow brake installation details.

Watch out: What happens if you defer installing snow guards on a roof where they're needed? Take a look at SNOW GUARD FAILURES and at PLUMBING VENT REPAIR and you can see both damage and how that damage was later repaired.

Our photo illustrates snow guards installed over the surface of the metal roof/facade of the VIA building in New York City.

As you will see below, this roof and facade follow a varying curve and slope making access, cleaning, and maintenance a challenge - met by special access machinery mounted to travel along a rail on the left edge of the structure.

...

Continue reading at SNOW GUARD GLUE ON INSTALLATION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• SNOW GUARDS & SNOW BRAKES
  • SNOW RETENTION SYSTEM HARDWARE
  • SNOW GUARD FAILURES
  • SNOW GUARD MOUNTING METHODS
  • SNOW GUARDS on METAL ROOFS
  • SNOW GUARD GLUE ON INSTALLATION
  • SNOW GUARD CLAMP ON INSTALLATION
  • SNOW GUARD SPACING & PATTERN
  • SNOW GUARD BUILDING CODES?
  • SNOW GUARD PRODUCT SOURCES

Suggested citation for this web page

SNOW GUARDS on METAL ROOFS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING ROOFING

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