Snow Guards… don’t they all work the same?
Over the years, we have seen our share of “snow guards,” and throughout the years, we have been contacted to fix what some people in the industry call snow guards. What many fail to realize is, a snow guard is an integral part of a metal roof and should be designed for each specific roof;
“A snow guard is a device or system that increases friction between roof and snow, retaining a snow pack on a roof, so that it evacuates in a predictable and controlled fashion (evaporation and thaw) rather than by a sudden and dangerous rooftop avalanche”. (Use of Snow Retention Devices Science or Science Fiction? S-5! AIA Presentation)
Exposed Fastened Roof Snow Guard
Below are images of a “snow guard” that is a commonly used system across Canada and more times than not it simply fails causing damage to roofs, property and in the worst case scenario injury or death.
These types of snow guards rely on the strength of sheet metal screws or the sheet metal itself to resist hundreds of pounds of snow and ice sliding down the roof; neither the screw or the sheet metal were designed for that. The sheet metal screws are designed to secure a metal roof to wood or purlins and that is it; they were never designed to resist the impact loads of snow sliding down a roof which is why they fail.
Why then do people or contractors keep using them… the up front cost is cheap for the contractor and the home owner, HOWEVER the cheap solution is going to cost the homeowner more in the long run. These cheap solution can cause serious damage to the metal roof to the point of tearing the rib of the metal roof and damage gutters!!!
What Can I do as a Home Owner or Business Owner to Avoid this Type of Damage ?
Believe it or not, there are companies who specialize in snow guards who can recommend a snow guard system that will work based on math and science… not by guessing what MIGHT work. Sky Products Ltd has been in the snow guard business for 10 years and works with companies such as Work Monster Inc out of Timmins Ontario, and others across Canada to supply a properly designed snow guard system.
What is a properly designed snow guard system?
“The forces of snow on a rooftop can be mathematically calculated…and should be for any snow guard job. If done properly, this can insure against product failure”. (Use of Snow Retention Devices Science or Science Fiction? S-5! AIA Presentation)
A properly designed snow guard relies on a few things listed below plus other factors not listed;
- Roof Designed Snow Loads where the project is located
- Pitch of the Roof
- Eave to Ridge Length or Rafter Length
- Assembly Length
- Type of Metal Roof, Standing Seam or Exposed Fastened. If it is an exposed fastened roof we will need to know if it is secured to plywood, steel purlins or wood blocking.
- Has the manufacturer of the snow guard system performed load tests on their products if so ask to see them. If they cannot provide the load tests then walk away.
This all sounds expensive…
A properly designed snow guard may be more expensive up front than the cheap snow guard, but it is cheaper than having to replace damaged roofs and gutters, having the contractor come back 2 or 3 times and putting more holes in your roof hoping that it works THIS TIME! Snow guards should be a long term investment, just like your metal roof; when properly designed they will work as required for years to come.