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How Much Snow On A Roof Is Too Much? | A Brief Guide

Snow has finally started falling. As peaceful as a winter wonderland can be, homeowners know it can come with a world of questions. For example, how much snow can a roof handle?

If you're wondering how much snow on a roof is too much, you've come to the right place. Continue reading to learn how you can determine if the snow accumulation on your roof is a reason for concern.


Why Is Snow Accumulation on Your Roof Dangerous?


Freshly fallen snow looks beautiful on your roof, but it can be quite dangerous. While a small amount of fluffy new snow isn't cause for worry, this is a situation where "too much of a good thing" definitely applies.

Every roof can support a different weight. After this weight limit is exceeded, serious structural damage can occur. If the snow on your roof weighs too much, it can lead to cracks, leaks, and worse.

In some cases, snow can even cause your roof to cave in. Although this would require substantial snow accumulation on newer roofs, older roofs can cave in with significantly less. When a roof caves in, your family is at risk of injury or even death, and the cost to repair your structure is high.

A secondary problem can occur with snow accumulation on certain roofs. When the snow melts, it can become trapped on your roof. This can cause water damage, which leads to leaks and structural issues.

If the standing water freezes before running off your roof, yet another set of issues occurs. A solid dam of ice can become semi-attached to your roof. This adds additional weight and presents a safety hazard to anyone walking past if the ice dam breaks.


Determining How Much Snow Your Roof Can Safely Hold


It can be challenging to determine how much snow your roof can safely hold. Even with this guide, it's recommended you contact a professional anytime you're uncertain.

Before anything else, you need to determine the maximum weight capacity of your roof. This information can be found in your roof's guide or warranty. But what if you don't have access to these documents anymore?

People misplace things, especially when many years have passed since you last replaced your roof. Try contacting the company who installed your roof. If you either can't get in touch with the roofing company or don't know who they were, you can search online for information.

Still lost? Call any roofing company in your area to see if they can give you an idea of your roof's weight capacity. Most newer roofs can hold at least twenty pounds of weight per square foot, but this can vary wildly.


How Much Does the Snow Weigh?


Once you know your roof's maximum weight capacity, you need to figure out how much the snow atop it weighs. A general rule of thumb is to use the 10-to-1 ratio rule.

10 inches of fresh snow = 1 inch of water
1 inch of water = about 5 pounds per square foot

Using this estimate, you can easily estimate the weight of snow. If your roof holds 20 pounds per square inch, you won't need to worry about snow accumulation until it reaches 40 inches. Of course, there are limitations to this rule.

Other factors come into play when determining weight that can make the task more difficult. If the snow is wet and heavy, it can weigh up to three times as much as light, fresh snow. The structural design of your roof and the materials it's made of should also be considered.


What's the Roof's Structural Design?


If your roof has a steep pitch, snow is less likely to accumulate, to begin with. Even when snow does accumulate, the risk of standing water is significantly reduced. Generally, melting snow will run off the steep roof sides before it has a chance to harden into ice.

If your roof is flat or has a minimal pitch, the risk of snow causing issues is severely increased. For starters, the snow is more likely to accumulate in high amounts. It's also significantly more likely to cause water damage or create ice dams.


What Materials are Your Roof Made From?


The best roofing material for snow accumulation is metal. Metal tends to have higher weight capacities and holds up reasonably well to significant snow buildup. Some metal roofs even have heaters located beneath to help the snow melt away before it can accumulate.

Asphalt and slate shingles also do well with snow if they're made from high-quality materials. The materials your roof is made of is one place where you don't want to skimp on the quality of materials.


When Should You Worry?


There are some times when worrying is called for. When it comes to snow on your roof, you should generally worry if:

  • Large amounts of snow have accumulated
  • Your roof seems to be sagging
  • Creaking noises are coming from your roof
  • Your roof was replaced more than ten years ago

Whenever you're in doubt, it's best to call a professional roofer. They can help assess the situation for you and let you know if worrying is necessary.


How Much Snow On A Roof Is Too Much? Know For Sure With An Assessment.


How much snow is safe on a roof? The answer varies based on your roof's maximum weight capacity, structural design, and materials. Whenever you're in doubt, it's best to ask a professional for an assessment.

Do you have more questions about how much snow on a roof is too much?

Contact us today. One of our professional associates would be happy to answer any questions you still have.

Posted by:
December 15, 2020
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