How Much Snow Can Your Roof Hold?
Thankfully, most homes in Michigan are built to withstand significant snowfall, but how much snow is too much? Learn more.
Thankfully, most homes in Michigan are built to withstand significant snowfall, but how much snow is too much? Learn more.
It’s finally winter, the most wonderful time of the year, when the threat of heavy snowfall is always around the corner.
While schools might close, roads may get slick, and you may have to prep your snowblower for what’s to come, one thing you typically won’t need to worry about is how well your home will handle significant snowfall.
Even if you get six inches of snow, it’s unlikely that your roof will croak “My time has come” before caving in. So, the next time there’s heavy snow in the forecast, take a deep breath, go to the store to get your milk, bread, and eggs, and don’t feel the need to climb onto your roof to clear any snow.
Let’s take a deeper look into just how much buildup your roof can handle.
The actual weight of snow buildup your roof can adequately hold will also depend on several factors, including the design of your roof’s framing, the quality of your roof decking, the location of your home relative to its typical winter climate, and whether you have one or two layers of shingles. In Michigan, homeowners can have up to two layers of shingles on their roofs. If you have a second layer, your roofing system is already supporting extra weight, so it won’t be able to hold as much snow as a single-layer roof.
If you have an asphalt shingle roof, you can expect it to hold up to 20 pounds of snow per square foot (or 10 pounds per square foot if you have two layers of shingles). So, if you have a typical 1,000-square-foot roof, it can hold 20,000 pounds (or 10,000 pounds) of snow. That’s more than you probably thought, right? It’s hard to imagine 20,000 pounds worth of snow, so picture a standard RAM truck in your mind, which weighs a little over 6,000 pounds. While we wouldn’t recommend it, you could technically place three trucks on your roof, and it would handle the weight just fine.
Keep in mind, too, that a foot of fluffy, powdery snow weighs about 4 pounds per square foot, while normal snow weighs more than 6 pounds per square foot, and wet snow weighs around 12.5 pounds per square foot. We’ll let you do the math based on your roof, but the bottom line is that in most cases, your roof can handle any significant snowfall just fine. Stay calm, and let it snow.
If you have a flat roof, whether EPDM or PVC, the same 20 pounds of snow per square foot rule applies. However, the primary factor influencing snowfall, aside from the roof’s age and current structural condition, is its central support.
Larger flat roofs are more susceptible to roofing damage from heavy snowfall in the center because there are longer spans between support beams. The closer the support beams and joists are together, the more weight they can hold. Beams will bend when weight is applied, but the amount of bending depends on how far the weight is from the nearest support joint. With longer spans, any weight placed on the beam has more leverage to create bending and will act like a lever. We know it’s winter, but think of a diving board—the further you walk out on it, the more it bends and bounces. It’s the same with support beams.
If your roof suddenly breaks while you’re sitting comfortably in your home watching National Lampoon’s Christmas Vacation, that’s when you know there’s too much snow on your roof.
We’re just kidding! Your roof breaking should not be a significant concern for you. We’ve been repairing and replacing asphalt shingles and flat roofs for decades, and we rarely see a roof collapse from substantial snowfall.
However, we’re firm believers in self-inspections. Trust your gut—if something feels off, it probably is. Whether you’ve experienced heavy winds, heavy rainfall, snow and ice, or a severe thunderstorm, if your brain ever says, “Maybe I should check on my roof?” Listen!
When performing self-inspections after severe weather incidents, look for:
Repeat after us: Do. Not. Climb. On. Your. Roof. You are not Spider-Man. The only outcomes from this are injury and embarrassment.
If you’ve experienced heavy snowfall, just let it be. Unless you’ve noticed any of the following signs, it’s unlikely to be a problem for your roof.
Here’s what we’ve seen homeowners do that actually causes more harm than good (other than walking on the roof):
✕ Using a Metal Shovel: Metal shovels are abrasive. If you’re not careful, you can damage your shingles. Even if you don’t have a shingle roof, there’s another important reason not to shovel snow on your roof—if you have a ton of buildup, and you’re shoveling from the ground, you’re just going to shovel snow onto yourself, and that honestly doesn’t sound like a good time to us. Even if you use a fancy snow rake or extended broom, that risk still exists, especially if you have a steep roof.
✕ Using Hot Water & Salt: Sometimes, modern problems don’t call for modern solutions. Some innovative homeowners will also use hot water and salt to melt snow. While they do work, are they worth the risk? Salt is corrosive. Sure, it may work the first time without damaging your shingles, but over time, salt use will damage your shingles. Likewise, hot water is only going to damage and discolor your roof, and you may end up scalding yourself with it, which, again, doesn’t sound like a good time.
✕ Using a Torch: We’re not even going to address this. Do you want to accidentally set your house on fire?
The best way to ensure safe, effective snow removal is to contact a professional for assistance.
We can’t say this enough—don’t panic after a heavy snowfall; very rarely will Michigan homes experience a roof collapse from significant snow buildup. However, a heavy snowfall may reveal other roofing issues that should be addressed. If you hear any obvious creaking or groaning, notice uneven thawing or odd snowmelt on your roof, or think anything else just seems “off,” your best bet is to schedule a professional inspection. It’s always better to be safe than sorry, especially during the winter.
L&S Home Improvements is committed to helping our communities stay prepared this winter. We strongly believe that the best way to prevent roofing problems, regardless of the season, is to stay on top of annual roofing inspections. These inspections ensure small problems are identified and resolved before they turn into larger, costlier ones.
No matter how cold it is, L&S Home Improvements is standing by to inspect your roof and attic. We’ll make sure you’re prepared this winter AND many more. Contact us today to schedule your free inspection.
