Don’t let heavy snow loads lead to roof collapse
Record snowfall across   the U.S. is increasing the danger of roof collapse and damage for   homeowners, businesses and institutions alike. But did you know that even   non-record levels of snowfall can lead to costly structural or water damage?   Even a small to moderate amount of drifting snow can unbalance a roof,   leading to localized loading, which can cause partial or total collapse.   Another potential hazard is plugged roof drains and gutters, which can lead   to large amounts of standing water, leaks and freezing damage.

While the temperatures are low,   the weight and density of the snow are relatively low. This is the typical   fluffy snow which can fool us into thinking that we are not at risk for   damage or collapse. But that same snow can act as a sponge when temperatures   increase or when heavier, wetter snow and/or rain falls. The weight captured   on a roof can increase tenfold-and the risk of collapse increases as well.

The following are some tips to   consider in the prevention of roof collapse or damage from snow and ice:

  •  Know the weight your roof can support. Enlist a structural engineer to assess the weight that your buildings can support and determine if any improvements are needed to prevent a future collapse. You can find weight guidelines published by IIBHS here.
  • Regularly inspect the roof and structure (inside and out) for any damage, cracks or corrosion. If you see signs of damage, contact a qualified builder/roofer to assess the extent of damage and make repairs as soon as possible.
  • Inspect  all roof drains and gutters for debris. Ice accumulation along the eave can contribute to roof collapse. Keep drains and gutters clear of leaves and other debris as a rule.
  • Know your risk. Some roofs have characteristics that are at a higher risk for collapse, including large, flat roofs with less than a 30º slope; roofs with heavy insulation; roofs that have had previous structural damage or stress; and roofs with shaded areas where snow sits longer and freezes into ice. Also, wood bowstring truss roofs are historically prone to collapse because of truss deterioration where it meets the wall.
  • Remove snow from roofs as quickly as possible after snowfall. Consider hiring a contractor who understands the safety measures to take and owns the proper equipment. If you do decide to have your employees remove snow, make sure they have proper training and equipment.