Snow Retention Systems: Does Your Roof Need One?

When considering whether to install a snow retention system on your roof, you may first want to consider what type of roof you have.  Will your roof allow snow to slide?  In places with heavy snows, like areas in Utah, it is common for snow to slide from certain types of  roof systems causing heavy ice and snow build up to sit in gutters, which causes damage over time.  If you have a metal, tile, slate or Membrane roof with a pitch of 1/12 or greater, snow may slide off and cause this problem.  Gutters will either hold the heavy snow, or they will fall, creating costly repairs.  

More often than not, when a customer wants a metal roof, they are excited about the idea of snow sliding off.  But after the first few snow storms, these customers see the down side to snow sliding off and piling up on the ground.  There are four main downsides to this occurrence:  
  1. The first is safety.  People commonly under estimate the weight of a couple cubic yards of snow.  And if it is mixed with ice at the eaves as is usually the case, it can cause serious injury and even death if it lands on someone.  
  2. The second is if snow that is fluffy while on the roof, falls ten feet and lands on the ground, it packs in and becomes very hard and dense.  It takes a steel shovel and even a pick in some cases to get it moved off a drive or walk way.  
  3. The obstacle that snow sliding off a metal roof can cause is damage to common roof penetrations and gutter systems.  Plumbing and Heating ventilation pipes can bend over from the sliding snow.  The weight of snow will drop gutter systems.
  4. The fourth is the thunderous sound it makes when it lands, and damaged landscape and railings that go with it.  I had a customer tell me she thought her house was collapsing as the 300 lb block of snow fell from the roof onto her deck.  This happened at night so you can imagine the adrenaline she woke up with!  We have a cabin that we let the snow slide off of and it damaged a log railing system, requiring a roof peppered with snow retention clips just to keep the snow from landing on the railings.
To prevent this, you can simply put snow retention clips on your pitched roof above the gutter and throughout the problem area to keep snow on the roof and to keep it from sliding.  For example, you may want more retention clips in areas above a patio, walk way, or driveway to prevent large amounts of snow from falling and damaging the property or even worse, causing serious injury to pedestrians below.  It can be safer for your roof, your gutters, and the area around your home if your snow is allowed to thaw instead of evacuate your roof by avalanche.  There are 3 main types of snow retention systems for metal and tile roofs:
  • Snow Fences
  • Snow Brackets
  • Snow Clamps
All three choices are effective at keeping snow on your roof.  However, snow fences are probably the best choice for a metal panel roof.  For a standing seam metal roof, snow clamps are usually the recommended choice.  For tile or slate roofing systems, you may want to choose snow brackets as a retention system.

For TPO roofs, even with a low slope of 1/12, it is recommended to install a snow retention system in areas with moderate to heavy snowfall.  If the snow is allowed to flow with the slope of the roof, it could build up in one area, causing damage to your roof and drainage system.  However, snow clips and fences are not usually as effective because TPO membrane is a flat roof system.  This means that, without proper precautions, the moisture could sit around the fasteners that hold the snow fences on and cause leaks.  The best course of action in this situation is to install clad metal on the TPO roof to hold the snow.  Brady Roofing is able to fabricate this metal in shop, as well as install and seal it properly on your TPO roof.  

My advice when designing building a roof system is simply this:  Check with building code requirements in your area to find out the snow load, have the roof design reviewed by a residential structural engineer, then keep the snow on the roof using the proper method.  Shingled roofs generally don’t have an issue with snow sliding.  If you are looking at a smooth surface roof system, and you have a visible slope, you will want to consult with a roofing contractor to see the best method for keeping the snow on the roof.  

For more information on snow retention systems, or for a free estimate, contact us today.  
 


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