Snow Retention Systems

A snow guard system mitigates the risk of sudden and unexpected release of snow from the roof, which can lead to damaged roof panels, gutters, light fixtures, walls and foundations, protection of lower roofs or worse, severe injury to people.  The idea is to evacuate the snow in a predictable and controlled fashion, as opposed to a sudden release.  It may be hard to imagine that an accumulation of those pretty little snowflakes can have enough force to do serious damage to property and person, but that is the reality. Shop our snow retention systems here.

Snow retention has been used for hundreds of years in regions where snow accumulation on roofs is an issue. Technology has now changed from stones and logs to polycarbonates, zinc and aluminum.  With the growing trend towards a more environmentally friendly construction industry, metal roofs in the commercial, industrial and residential markets are quickly becoming a choice of architects and roofers. Metal roofs are made from recycled material (steel and aluminum), and their longevity greatly surpasses that of a shingled roof. A metal roof can last upwards of 80 years and their reflective properties equate to lower cooling costs in the summer.   With every new metal roof installed, there needs to be a properly designed and engineered snow retention system.  A properly designed system needs to take into account the following factors:

Can the manufacturer provide load tests on the attachment method to the metal roof whether it is a standing seam or not?  Are the manufacturer’s published load tests based on ULTIMATE loads or does the manufacturer provide both the ULTIMATE and WORKING loads? Working Loads are generally based upon a Safety Factor of 2 of the Ultimate Load, example below

  • Manufacturer’s load test shows the attachment point to the metal roof has an ultimate load of 1000lbs, the ultimate load generally indicates some point of failure depending on the manufacturer’s testing protocols.  Some manufacturers post the ultimate load as their working load which can quickly overload a snow retention system and possibly cause damage to the roof panel itself. An industry standard is to apply a Safety Factor of 2 to the ultimate load, which would be 500lbs; essentially dividing the ultimate load by the safety factor.  In some cases a safety factor of 3 may be applied.  

Are these results available upon request or do they magically appear when it comes time to close the deal.  If the manufacturer CANNOT provide you with any load tests that have been certified by an independent lab or have been stamped by an engineer, then it is buyer beware.


For Standing Seam Roofs

  • Roof Designed Snow Loads – these are based upon the National Building Code
  • Slope or Pitch of the roof
  • The distance from ridge to eave or the panel run of every roof that requires snow retention
  • The assembly length of every roof that requires snow retention
  • The gauge of the metal being used (copper or aluminum)
  • The profile or fold of the standing seam profile.  
  • Spacing between seams
For Exposed Fastened Roofs – also known as Screw Down Roofs
  • Roof Designed Snow Loads – these are based upon the National Building Code
  • Slope or Pitch of the roof
  • The distance from ridge to eave or the panel run of every roof that requires snow retention
  • The assembly length of every roof that requires snow retention
  • The substructure to which the roof is attached (steel purlin or plywood)

Further considerations are dormers, overhangs and adjacent roofs that may shed onto a lower roof(s).