After a heavy snowfall and potential freezing rain, the Agency of Agriculture urged farmers to take precautions to avoid collapse of their barn roofs.
It's important to understand how much your barn can withstand and what to do to keep your livestock safe. Many agricultural buildings in Vermont are designed for "total" roof load of 50 pounds per square foot. This includes the dead weight of the framing, trusses, rafters and ceiling. Add this to a few feet of snow and the weight on the structure begins to exceed its carrying capacity.
Another important thing to consider in snow loads is that a roof may be able to hold a heavy load for some time, however, it may not be able to hold the increased load for the rest of the winter or through another storm that produces significant accumulation. A roof can loose its structural integrity after about 30 days if it is not cleared. The threat of these conditions makes it imperative to remove the snow from the building as soon as possible.
"Removing snow from the roof of farm structures as it accumulates is the best way to avoid a collapse and potential damage or injury to you and your livestock," advises Anson Tebbetts, deputy secretary for the Agency of Agriculture.
When clearing snow from a roof, work to ensure an even unloading from both sides at a time. Always work in pairs and use a safety line when clearing steep pitched roofs. Try to plan an escape route before you begin and keep safety the first priority. The center of the rafters and the center of the building are the weak points. It is advised to keep some 4x4 or 6x6 poles on hand to place under every fourth rafter, or along the center of the roof line. This will provide additional strength to the roof.
If you are unsure about the structural integrity of you barn you may want to consult a professional engineer to assess the condition of the building. Even barns that survived the last storm may have hidden structural damage that might not be apparent until the next snowfall. A registered, professional engineer can provide a structural review of your building and assist with a summary of improvements, if necessary.