Assessing Your Roof’s Snow Load Capacity: What You Need To Know

Most modern roofs are built to withstand a certain amount of snow load. However, when a building’s structure is overwhelmed by a lot of wet and packed snow, the result can be roof sagging and ceiling leaks.

Calculate Your Roof’s Weight

Even though most new structures are built to withstand a certain amount of snow, any structure can suffer damage from too much weight. The first sign that the load-bearing capacity of a building is being exceeded is often a visible sagging of the roof or horizontal deflection of walls. Performing a simple visual inspection to estimate the current snow load on your roof is possible. However, it is best to use a roof snow load measurement calculator for this purpose since the exact calculation depends on the construction of your roof and local building regulations. The simplest method for calculating the current snow load on your roof is to measure the depth of the snow in feet and multiply it by the weight of one cubic foot of snow. This is 6 to 8 pounds for fluffy snow and 20 pounds for ice. Once you have this number, you can compare it to the permitted load set by your local building codes.

Calculate Your Roof’s Pitch

Many factors impact how much snow a roof can hold. It depends on the density and depth of the snow as well as the roof’s pitch. A roof’s pitch is the ratio of its rise (height) to its run (horizontal distance). To determine a roof’s pitch, mark a level at 12 inches from the bottom of the level and then measure the distance from this spot on the ground to the top of the roof ridge. This number is the roof’s pitch. While most newer roofs are constructed to withstand a specific amount of weight from snow, older structures may not comply with current building codes. It’s also important to monitor the type of snow accumulation and temperature as these will change over time and can impact a building’s snow load capacity. This will help ensure the structure is not at risk of structural failure. Snow accumulation can also cause ice buildup that needs to be addressed quickly to prevent damage to the roof.

Determine the Depth of the Snow

One of the first things you must determine is how deep the snow is on your roof. You can do this using a tool like a snow stick or a simple ruler. Take multiple measurements and then average the results. Be sure to measure from a flat surface and away from snow drifts. Once you know how much the snow is, you can calculate its pressure on your roof. To do this, divide the total depth of the snow by the weight of one cubic foot of snow. This will give you the number of pounds per square foot your roof can handle. All structures, including metal buildings, are built to withstand a specific design snow load. They will provide this information if the blueprints and construction documents are available. However, proper building materials or poor building maintenance can prevent the actual load from being lower than the design load.

Calculate Your Roof’s Density

Unusually heavy snowfalls lead to many things: stalled cars, snowball fights, and, for homeowners, concerns over their roof’s ability to hold the weight. This is because roofs are designed to withstand a specific load, known as the snow design load. Fortunately, some simple calculations can help you determine whether your roof is in danger of reaching its load capacity. First, you must consider the density of the snow. Packed snow is more dense than loose, fluffy snow. Generally, three to five inches of packed snow correlates to one inch of water and about 5 lbs per square foot of roof space.

Author: Giuliano Forti