In many parts of the country, ice and snow coverings are typical with winter. Although it may look beautiful, it can be devastating to building roofs and structures. It is important to know how to calculate snow loads for buildings and the factors that may affect them. This post examines snow loads, designs, and removal of snow to maximize the safety levels for your structures.
Designing Steel Roof to Optimally Manage Snow Loads
The best defense is to take the offense and prevent it at the start. There are many considerations to factor in mitigating snow damage issues, including wind exposure, roof shape, and pitch.
Roof Shape including Pitch and Slope
In snow-prone areas, it is important to take into consideration the shape and pitch of the roof. A flat roof without any obstructions typically was uniform in snow load distribution. Roofs with irregularities or obstructions may create unbalanced snow accumulation. Higher pitched roofs tend to shed snow better, than flat or low-pitched roofs.
It is recommended to contact your contractor to verify the materials and shape of your new buildings. The shedding of snow loads gradually is much more preferable to prevent injury or damage to people and other objects by falling snow.
Thermal Conditions of Buildings
It can be important to keep your roof cold to prevent ice dams and rims of ice that may trap water and cause further problems. A cold roof can help keep snow on a roof to stay frozen, this is important to prevent thawing snow to create water runoff and create additional issues. Accumulation of heat in an attic due to wall gaps, unblocked walls, openings around pipes, and other fixtures can keep the ceiling warmer and melt the bottom layer of snow.
Melting snow can cause ice dams that may ultimately lead to leaks damaging ceiling, walls, roof structure, and insulation. Eventually, the ice dam may break down and fail, releasing with enough force to bring snow or even equipment down with it. This may not only create significant damage to a roof, but it can also create safety hazards with serious injury potential.
Help keep the roof cold and prevent ice dam formation by ensuring effective insulation between the attic and ceiling. If your building or warehouse has an attic, make sure the heat does not become trapped to warm the roof. The introduction of cool air along with efficient insulation helps ensure maintaining a cold roof.
Consideration for Roof Material and Obstructions
The snow burden on warehouses or other structures can be reduced by utilizing steel roof panels. The steel panels offered by Allied Steel Buildings are manufactured to gradually shed snow or ice and better resist cold weather damage. Even with the finest products, obstructions such as pipes, vents, HVAC, and firewalls can lead to uneven snow load distribution. Any of these conditions can affect a building’s integrity and require being taken into account when calculating snow loads.
Consideration for Building Locations and Wind Exposure
Often, a steel warehouse may be built-in open, windy areas. The windy area may keep the snow load manageable by carrying the snow away, while sheltered building locations can encourage snow accumulation. However, if there are multiple roof elevations, rooftop equipment, or rooftop equipment it can promote snowdrifts. Accumulated snow due to snow drifting can lead to unbalanced snow loads, affecting rooftop conditions.
Tips for Snow Load Removal
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The best structural designs to combat and manage snow loads and ice dams will at some point have snow accumulation. When this happens, it is best to focus on selecting the correct snow removal process. It may be necessary to remove snow for every 6″ of accumulation to mitigate ice dam creations. If the formation of ice dams is not a major consideration, then snow removal at 12″ depth should be okay. Every snow removal situation is unique, and ideal snow removal timing may be dependent upon factors such as roof geometry and building design. In addition, other factors to be considered are snow density, distribution, accumulation, snow drifting, and sliding.
Snow-Removal Practices Commonly Include:
Raking of the Roof:
Single-story and small buildings having the roof raked of snow is probably the best option. Taller buildings can benefit from raking overhangs to clear snow, which typically is the weakest part of a roof. A side benefit of raking overhangs is helping to prevent potentially dangerous ice dams.
Select the better roof rakes with bumpers or small rollers on the blade bottom. Try to avoid chipping and picking at the ice, this may cause unexpected damage to the roof below. Furthermore, it is a good idea to purchase extra rake extensions for reaching higher up on your roof.
Roof Shoveling
When the snow is hard, heavy, or wet, shoveling may be the best option when a rake is just not effective. If the snow load condition requires shoveling, it may be best to have professionals perform the clearing. Large, tall roofs and heavier snowfall than rakes can manage also are best dealt with by shoveling. When contracting with a professional for the shoveling, make sure they use tools that will not damage the roof. It is also important to ensure the professionals do not leave footprints in packed snot on the roof, as they may ultimately create ice dams.
Remove Snow in Narrow Strips:
Also, keep in mind, experts recommend removing snow in narrow strips to maintain an even snow load for the roof. This should be considered whether you employ professionals or decide to do the job yourself to remove the snow.
Regardless of the snow removal process selected, you should leave at least a couple of inches of snow on the roof. The snow remaining provides a safety blanket for any damage that could have happened during the snow removal process. Managing risks include wearing appropriate safety gear and maintain awareness of your surroundings for dangers that may be present, such as power lines.
Discover the Snow Load Requirements in Your Area
The Metal Building Manufacturer’s Association’s (MBMA’S) Code of Standard Practice sets the codes to be used for your building. Manufacturers like Allied Steel Buildings cannot select what code to your project. This has to be determined by typically the engineer or architect of record, the local building department, or the local permit official for your building.
It is important to ensure you are using the correct materials for your building with the right load levels by checking the construction codes.
To protect your new building during winter weather conditions, make sure and contact Allied Steel today and visit one of our experts.