Calculating Roof Snow Load

To calculate the weight of the snow and ice on your roof, use a calculator that allows you to enter a number in kilograms (kg) or pounds. The calculator will then compare the total weight of snow and ice on your roof to the allowed load. The calculations are based on standards established by the American Society of Civil Engineers (ASCE) in the 1988 Minimum Design Loads for Buildings and Other Structures. The ASCE7-16 standards are updated periodically. Those houses built before the standards were set still follow the same process.

Calculate the weight of snow on your roof

To determine how much snow is too heavy for your roof, you should calculate the weight per square foot of the total snowfall. For example, one inch of light, fluffy snow weighs about 4.1 pounds per square foot, while two feet of wet, heavy snow weighs approximately 11 pounds per square foot. In addition, you should consider the weight of ice, which is more severe than snow, which increases the weight even further. Finally, you should consult a local weather expert to determine how much snow is too heavy for your roof.

It can be challenging to determine how much snow is too heavy for your roof based on snowfall totals. Snow weight depends on many factors, including the type of snow and its density. Here are some tips that can help you determine the importance of snow on your roof:

Calculate the maximum weight of snow allowed on your roof

Various factors determine the roof snow load measurement and the maximum weight of snow that can be placed on your roof, including the rafters and the structure of the home. Consequences are also significant, especially when considering the safety of your roof, as snow weight is measured in pounds per square foot. Snow is generally considered heavy when fresh and weighs around 4 pounds per square foot, but the weight can be more or less depending on the snow type. New snow tends to weigh less than old, compacted snow, making calculation an exact science.

Typically, snow load calculation is done with a formula based on the roof type. For example, a flat roof is less likely to bear the weight of heavy snow than a sloped roof, so you should use this formula when calculating the weight of snow. In addition, you may use a yardstick to measure the snow depth and give the measurements in feet, not inches. Once you know how much weight your roof can bear, you can determine whether you should add additional support or remove the top altogether.

Calculate the slope of your roof

One of the first steps in determining the slope of your roof is its height. The gable end is the most convenient location to measure the slope of your roof. Place a level against the underside of the rafter and measure the distance from the bubble to the top of the roof. You may find that the distance from the level to the rafter is about 12 inches. Subtract this number from the original measurement to determine the slope of your roof. Once you have measured the height from the level, you may multiply that height by the slope multiplier.

Generally, roof pitches vary from 4/12 to 9/12. The most accurate way to measure the slope of your roof is to use a level and mark the level with a 12-inch mark. Then, measure the vertical distance from the level to the rafter to determine the slope of your roof. If the slope is more than 12 inches, use the tan (degrees) formula. This formula will give you the slope of your roof in inches per foot.

Calculate the weight of ice buildup on your roof

In determining how much weight your roof can bear, you should start with the volume. For example, a one-inch-thick layer of snow can weigh up to twenty pounds per square foot, so a roof that supports up to four feet of snow could theoretically support the weight of four inches of ice. However, when you add the importance of wet snow and ice, the weight can reach sixty pounds per square foot, which is more than most roofs can handle.

Another way to assess the weight of ice buildup on your roofing system is to use a snow load calculator. This tool calculates the total weight of the snow and ice on a specific area of your roof. You can find this information by entering the site you wish to consider and the number of square feet or meters. If you find the number of icicles or snowfall on your roof is more than you expected, you should check out the area around your roof and make any necessary repairs.