Freshly fallen snow brings a peaceful serenity to any landscape, but when the snow piles up, it can signal danger for your home's roof. How much snow can a roof handle? The answer depends on many factors, including the style and location of your home, the amount of snow your region receives on an annual basis, and whether you've stayed on top of preventive maintenance items before the snow arrives.
Read on to learn more about snow loads, the factors that affect them, warning signs to look out for, and when it's time to call in a professional to clear snow from your home's roof.
How Much Snow Can a Roof Handle?
Roof snow load is the amount of weight and downward pressure on a roof caused by a buildup of snow and ice on the roof's surface.
Every roof is different when it comes to the amount of snow load it can withstand due to varying factors, such as pitch and exposure to the sun. Whether the snow is light and fluffy or wet and dense plays a role, as well, which is why it's not possible to use a one-size-fits-all number. Many roofs are designed to withstand a 20 pounds per square foot baseline number when it comes to roof snow load, but again, this can vary.
Not all snow weighs the same, either. One foot of light powdery snow can average around five pounds per square foot versus one foot of heavy, wet snow that can weigh 20 or more pounds per square foot.
Your roofing system has to work hard to withstand the challenges that come with different types of seasonal weather, which is why taking precautions and having regular inspections are so critical to continued performance.
Factors That Affect Roof Snow Capacity
Roof design and slope. The steeper the pitch of your home's roof, the easier it is for snow and ice to melt and slide off, whereas any flat roof surface areas need more time for snow and ice to melt and drain or evaporate.
Materials and age of the roof. All roofing materials will experience weakening or degradation over time, which is normal and to be expected, but this can affect the roof's ability to withstand roof damage from snow and ice over time. Also, any areas of the roof that have previously been compromised or experienced storm damage won't have the same tolerance for snow loads as newer materials.
Regional building codes. If your home is located in a geographical area that experiences snowy winters, your local building codes likely take this into consideration. Such areas often require stronger underlying support systems that can bear the weight of heavy snow loads.
Underlying support systems. Your attic framing and the condition of the beams play a role in how much roof snow load your home can support. If your home is older and the beams are weakened, they won't be able to hold as much weight as newer, stronger beams. Think of your roof the same way you would a shelf. The shelf can only hold as much weight as the supporting brackets underneath it can bear.
Not All Snow Weighs the Same
When asking how much snow can a roof handle, the answer will also vary depending on the type of snow that's fallen. Fresh, powdery snow is the lightest, with the weight of this type of snow coming in around five pounds per square foot. If you've ever tried to make a snowball or build a snowman with light, powdery snow, you understand that it doesn't contain enough moisture for the flakes to stick together to form a ball of snow.
Once the snow has time to settle or compact, it becomes heavier. The freeze/thaw cycle of the snow will cause the moisture level to increase, resulting in a heavier weight for the snow sitting on your roof.
If the snow that's falling is wet and dense, it makes for great snowman building and snowball making, but it's the heaviest type of snow that causes the most stress on your roof. This type of snow can weigh 20 pounds or more per square foot, which can lead to significant stress and potential damage to your roof. The formation of ice or the development of icicles can also lead to damage and reduce the snow-load tolerance of your roof.
Warning Signs of Too Much Snow on a Roof
If you have a buildup of snow or ice on your roof, you may be wondering how much snow can a roof handle? Start looking for warning signs of roof stress to determine if you need to contact a professional for help. You'll want to perform a visual inspection to find out if it is leaking by looking for signs of trouble on both the exterior and interior of your home.
From the ground level, look at your roofline to see if it appears to be sagging or if there are visible uneven surfaces. Check the gutters to see if they're starting to pull away from the home, as this can be a clear sign of damage.
Inside your home, check your attic for signs of moisture penetration or damp insulation. Examine your ceilings or walls for water-related staining or cracks in the drywall. Doors and windows that suddenly start to stick can also be signs of damage from snow. If you hear popping or cracking noises or notice that your walls are starting to bow, consider this an emergency situation, and call an experienced professional as soon as possible.
Snow Removal: Why Professional Help Matters
Snow load roof safety should be top of mind when it comes to using a ladder or climbing on your roof when snow and ice are present. Always start with options that let your feet stay firmly planted on the ground, such as an extendable roof rake that can reach the lower areas of the roof, allowing you to clear snow from the edges.
If the snow on your roof is very deep, compacted, or icy, it's time to call in the professionals. Roofing contractors are experienced in dealing with snow on roofs and have the proper equipment and safety gear to tackle the issue without jeopardizing the roofing system or their team members' safety.
Trying to do it yourself can lead to damage to the shingles, potentially voiding the roofing system warranty and risking injury to yourself. It's best to prepare your roof and have a plan in place, including a contractor to contact, ahead of the storm.
Protecting Your Roof Investment
Snow load varies by roof type, the age of the roof, the density of the snow, and the region where you are located. Take snow load roof safety seriously and try to mitigate the risks before winter by prepping your roof for the snowy season.
Watch for warning signs, take action from the ground, and call in the professionals to tackle the tougher snow removal jobs. You may also want to consider getting a post-snowstorm roof inspection after everything has melted to ensure your roof is in tip-top shape.
