What’s the snow load for my barn roof?

by horselover2


For most of the US, winter is difficult but not horrendous. Winter usually brings bored horses, icy roads and slippery turnout conditions. But this winter is all that and more. In the past few weeks several horse barns and indoor arenas have collapsed from winter snow storms. Some horses were lucky enough to get out alive, others had to be euthanized.

Although it’s difficult to outsmart nature, there are steps horse owners and farm managers can take to make their barns and other structures safe from winter’s fury.

“Before winter arrives, ensure that any new roof has been built according to building codes, the roof is structurally sound, has its shingles intact so that they do not blow off creating leaks or a danger to animals, and consider installing snow slides that can help remove snow,” said Dr. Jenifer Nadeau, a University of Connecticut equine extension specialist.

“In an area housing horses, we need to have minimum amount of airflow to maintain good air quality year round,” said Dr. Larry D. Jacobson of the University of Minnesota.  “That’s the only way to remove excess moisture from the barn and keep the barn free of gasses, like ammonia.” Excess moisture can weaken wooden structures.

“Also, keep gutters clean and free of debris to prevent ice buildup leading to ice dams and roof damage,” Nadeau added. She also suggests having an evacuation plan and practicing what to do in the event of a roof collapse.

“Typically the snow load isn’t too much of a problem for buildings with metal roofs because it tends to slide off when the temperature warms up a little,” Jacobson said, adding that it’s common for snow to only remain on a roof for a few days. “There might be some situations where we get freezing rain and the snow falls on top of that, but that will also slide off when it gets a little warmer.”

“But most structures are safe for 20 to 25 pounds of snow loading per square foot, with some of the newer constructions being good for probably 30 to 35 pounds per square foot,” he continued, noting that buildings in warmer climates might have a lower snow tolerance than those built-in northern climates that receive a large amount of snow each year. He said it would take “several feet of snow” to approach the limits in northern barns.

Both Nadeau and Jacobson suggest hiring a professional to remove snow from the roof if it seems like it might collapse. Visual changes in the structure and cracking or squeaking noises might indicate the roof is under stress.

Jacobson noted that the buildings typically at greatest risk of suffering a collapse are ones with large spans between supports, such as indoor arenas.