reposted with permission - original post can be found at http://blog.s-5.com/blog/what-snow-guard-is-on-your-metal-roof
Sky Products Ltd and S-5! Metal Roof Attachments.
Sky Products Ltd has been a proud stocking distributor of S-5! since 2010 and since then has grown to be the number one source in Canada for anything S-5!. With the newest update to the National Building Code of Canada 2015 that addresses snow guards "for a guard to be considered effective in retaining snow, it must be constructed of horizontal railswith a minimum diameter of 25 mm spaced no more than 100 mm apart”. Structural Commentaries (User’s Guide – NBC 2015: Part 4 of Division B), it is important to work with a company who can provide a proper snow guard solution for your specific roof! Sky Products Ltd recommends S-5! products as they have been rigorously tested in both laboratory and field conditions.
Snow Guards for Metal Roofs
At S-5!, we don’t recommend installing adhesive-mounted snow guards on metal roofs. From both an economic and design perspective, glued on plastic snow guards typically have low holding strength and are unable to handle harsh weather-related elements. The bond weakens over time and when it fails, the guard can rip away paint and protective roof coatings, potentially leading to corrosion.
Clear plastic snow guards are a misnomer in name too. Manufactured with petroleum derivatives, oils and plasticizers leach out of the material and cause the guards to yellow over time. In bright sunlight, they are highly reflective, so they tend to glow like light bulbs.
Beyond aesthetics, the progressively low failure load of plastic snow guards requires an over-populated (polka-dotted) design on the roof to prevent failure. When compared with our mechanically attached products, load test failure data has shown it can take up to 10 adhered parts to equal the strength of just one row of our ColorGard® system.
Keep Snow on the Roof
A snow guard system’s number one purpose is to hold snow back and allow it to leave the roof slowly, (in small amounts or as melt water). So, obviously a snow retention device must actually remain on the roof - for the life of the roof. But as S-5! has witnessed countless times over the years, adhesive-mounted snow guard systems generally fail long before the roof does.
The Definitive Source Also Agrees
The MCA (Metal Construction Association) technical documents are an additional aid for snow guard selection criteria. Document downloads are free. Visit MCA (then click on “Metal Roofs”) for more information. Download this comprehensive technical bulletin for invaluable information for helping you evaluate snow guard products and systems for proper performance and durability for the life of the roof.
So, What’s on Your Roof?
A quality snow guard system will help preserve your roof and allow snow pack to exit the roof in a more controlled manner. Learn more about installing snow guard systems and weather proofing at S-5.com.