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Ice damming | Roof Leak

Why Does Your Roof Leak When It Snows? (& How to Prevent It)

January 19th, 2022 | 5 min. read

Why Does Your Roof Leak When It Snows? (& How to Prevent It)

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Anytime we see snow on the radar in Middle Tennessee, we can count on getting calls about roof leaks. When this happens, the first question we ask is, “Does your roof leak when it rains too?”

The majority of the time, the answer we get back is no. Most homeowners are confused and don’t understand why their roof only leaks when it snows. 

For over 30 years, the team at Bill Ragan Roofing has helped homeowners understand the “why” behind their roof leak. Now we want to help you understand why you may experience leaks when your area gets hit by a snowstorm. 

We’ll start this article by getting right into why your roof leaks when it snows and the areas where it’ll happen. After that, you’ll learn if it’s possible to stop the leak once it starts happening. 

To finish this article, we’ll get to how you can prevent leaks when it snows in the future. 

Why does your roof leak when it snows?

The reason your roof leaks when it snows is because of ice damming. Ice damming is when snow and ice freeze down by your gutter line (eaves), creating an ice blockage (dam).

ice damming(Ice damming at gutter line)

Because of the dam, water can’t drain normally into your gutters when the snow above starts to thaw. This causes water to back up in areas and/or on materials that aren't supposed to have sitting water. 

With nowhere for the water to go, it eventually drips into your home. Unfortunately, this will continue until the ice dam completely thaws out. 

You might think this kind of leak means there’s a problem with your roof. Just know, this isn’t necessarily the case because most roofing materials aren’t meant to handle sitting water. 

The areas prone to leaks when it snows

Now that you know why your roof is leaking when it snows, you need to know the areas on your roof where an ice dam can form and a leak can happen. When it happens at the gutter line, the thawed snow/ice will back up until the water comes through your ceiling and even down your wall. 

example of areas where leaks will occur from ice damming

Ice damming can also occur in your roof valleys, around a roof cricket (diverter that sends water away from a chimney), and where a valley comes in against a wall (deadpan valley). These areas are crucial for water to find a pathway down to your gutters. 

example of areas where leaks will occur from ice damming

While they can handle running water, these areas aren’t meant to have sitting water on them. So, when there’s an ice dam or a blockage the thawed snow/ice has nowhere to go and can’t get to your gutters. 

This leads to a leak, and you’ll find water dripping into your home wherever a valley or cricket is located. 

Can you stop your roof from leaking when it snows?

Unfortunately, there’s nothing you can do to stop a leak from ice damming when it’s already happening. You can only do preventative measures during your roof’s installation when you get a replacement (we’ll get to that in a bit).

What a roofing contractor can do is come out to your home after everything thaws out to make sure your roofing materials aren’t compromised or damaged. When ice damming occurs, you may see some people on their roofs trying to shovel or rake the snow/ice off their roof. 

Not only is doing this a huge safety risk, but it also causes all kinds of damage to your roof. This damage could lead to spending a lot of money on repairs or could lead to a roof replacement if the damage is extensive.

The truth is, the only thing you can really do is make sure you have a bucket or some other container to catch the water and wait for the ice dam to thaw out. Just make sure to keep an eye on the bucket or container because you’ll be surprised how much water actually comes through. 

How do you prevent your roof from leaking when it snows?

Ice damming prevention is a code in a lot of Northern states, especially above the snow line. But if you’re in the south like we are, most homes aren’t equipped to handle ice damming. 

But remember, you can add preventive measures when getting a roof replacement. One way is to install ice and water shield at the edges (rakes and eaves) of your roof that goes 2 feet past the interior walls of your home.

ice and water shield on the edges of a roof(Ice and water shield on the edges of a roof)

This is a code in the states above the Tennessee/Kentucky state lines that get frequent winter storms. Just be aware, it’s considered an upgrade in areas like Tennessee and adds to the cost of your roof replacement

Another option to prevent ice damming is by putting the right materials in your roof valleys during your replacement. 

ice and water shield in valley(Ice and water shield)

The best way is by installing ice and water shield in all your roof valleys. But if you have a deadpan valley, it needs something solid (metal or a membrane material) installed in the valley and/or against the wall, so if the water does back up, it won’t seep into a crack. 

It is possible to retrofit a piece of metal or membrane into your existing roof if you have a deadpan valley. But this is something you’ll have to discuss with your local roofing contractor.

What kind of roof damage is covered by your homeowners insurance?

Now you know why your roof leaks when it snows, the areas prone to leaks, if you can stop it, and how to prevent leaks when it snows. But will the damage caused by a leak be covered by your insurance company?

Depending on your policy, they may cover the damage caused to your valuables and any structural damage caused by the leak. The real question is, will your insurance company cover the problem on your roof that leads to the leak?

The truth is, insurance won’t take care of every problem that leads to a roof leak. That’s why you need to know what kind of roof damage is covered by insurance. 

Since 1990, the team at Bill Ragan Roofing has provided high-quality roofing services to homeowners in Nashville and surrounding Middle Tennessee areas. No matter what your roof needs, you can count on us to take care of the problem so you’ll never have to worry about your roof again. 

To learn what roof problems your insurance company covers, check out What Kind of Roof Damage is Covered by Insurance.

storm damage checklist

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