Ice Dams in the Southern US
If you live in a part of the country that typically doesn’t force you to think about snow all the time, naturally you might not think about the damage it can cause until it’s already causing damage. As someone who professionally removes ice dams in Minnesota and other often-snowy states every winter, I’ve got a few suggestions as to what to pay attention to.
When you get heavy snow, you face two big threats: ice dams, and the possibility of suffering a roof collapse. If you’re not sure what an ice dam is, read my article, “What is an Ice Dam?” – which will give you a brief rundown on how ice dams form. In the meantime, know that an ice dam can cause your roof to leak and can cause major damage to your home. The scary part is all that’s needed is melting snow. Ice dams are something people in the north and in the Midwest have to deal with nearly every winter that there’s any amount of measurable snow.
Fortunately, ice dams and roof collapses don’t happen in a vacuum, and so you also aren’t helpless against them. Here’s what you need to know.
Watch the temperatures
Ice dams happen when snow melts at the top of your roof, and then re-freezes at the bottom of your roof (most commonly on your overhangs and in the valleys of your roof). This means daytime highs above freezing, and nighttime lows below freezing, are cause for concern.
DEFCON 1 – Threat Level Green:
You’re going to be fine if you are expecting highs in the 50s a week or so after the big snow. Your chances of having a problem are very slim, even if the temperatures drop down to 20 degrees at night. Those highs are so high that they ensure any snow will be gone pretty quickly, especially if you have dark-colored shingles and no nearby trees.
DEFCON 2 – Threat Level Yellow:
Things get a little more concerning if you are expecting highs in the 40s and lows that are below freezing. At this point you should seriously consider ordering a roof rake online (given that it’s unlikely you’ll find one at the local hardware store). Use my guidelines on safe roof rakes and on roof-snow removal technique to get the job done. When there is no snow on your roof there is nothing to create a problem. Even if you can’t get all of the snow, having less snow on your roof will decrease your chances of getting an ice dam and running into other problems.
DEFCON 3 – Threat Level Orange:
If you see highs in the low 40s or high 30s, and lows below freezing, you are experiencing excellent conditions for ice dams and you should definitely rake your roof when the combined accumulation of snow on your roof reaches six inches or more. Keep an eye out for any icicles, too (see below), because a warm attic could exacerbate your potential ice dam risk.
DEFCON 4 – Threat Level Red:
At this point, you’re seeing highs just above freezing and nighttime lows below freezing. These are prime conditions for ice dams. In fact, when we sit and watch The Weather Channel and notice another state with conditions like those, we get in our trucks. That’s because we know there are many people in that less-snowy state who will get ice dams and not know how best to handle. We’ll have traveled 2000 miles before our phones even ring, but we know exactly what’s going to happen.
If you’re one of those people, you need to get the snow off your roof now. You may even need to invest in professional snow removal so you can get all the snow off your roof. It will cost you anywhere from $750 to $2000 to do so, but you’ll be in the clear with no ice dams, no leaks, no damage, no repair costs, no insurance deductibles to pay, no higher insurance rates to pay, and no need to go to a hotel because your house is uninhabitable from all the damage. Getting the snow removed from your roof is the least-expensive, least-bad option.
DEFCON 5 – The Threat Is Here:
There’s something even worse than Threat Level Red: you have temperatures below freezing at night that don’t ever break freezing during the day. Why? Because while the temperatures remain constantly below freezing, the radiant heat from the sun will slowly melt the snow on your roof. People who live in regions that don’t get much snow tend to have insulation that is not up to the challenge of dealing with a lot of snow and ice, and they tend to crank up the heat far more than people in the north do. The result is you will also wind up with a warm attic, which will cause the snow to melt from the underside and slowly trickle down the slope of your roof. It will refreeze quickly because it’s very cold and the resulting ice dam will grow and spread before you even realize it’s there. You MUST get the snow off your roof if you don’t want to pay for a more expensive ice dam removal job, roof repair job, and major interior repair, later on.
Note that you don’t necessarily have to worry about your garage if it’s not heated. You just need to worry about the roof of your house.
Watch Your Icicles
Icicles are not just a pretty, whimsical winter experience. They’re often the first sign that ice dams have started to form. You need to watch the size and locations of these icicles to determine how dangerous conditions are.
Now, small icicles that spread out evenly over the entire edge of your roof typically are anything to get alarmed about. But if you start seeing large icicles, ice buildup on your overhangs, or even worse – icicles under the overhangs, you’re in trouble.
As soon as you notice the problem, you’ve got an ice dam and you need to call for ice dam removal right away. If you wait until there’s a leak into your home, you might not be able to get help quickly enough, as ice dam removal companies get very busy very quickly. We have a saying around here: “When one house leaks, they all leak.”
If you see ice on your siding you are in big trouble. You are likely to see a roof leak within the next 10 to 12 hours. In fact, there’s a good chance you already have a leak but don’t know it yet, because the insulation behind your walls and above your ceilings is soaking up all the water. Call for help right away.
Watch Snow Accumulation
Snow is heavy. On average, one inch of snow weighs one pound per square foot of rooftop.
That doesn’t mean every roof will collapse after every 24-inch snowfall. Many factors can lead to a roof collapse. For example, a flat roof typically is much more susceptible than a pitched roof is. The age and health of your roof can make a difference, too. How wet the snow is can make a difference: one inch of light, powdery snow can be much lighter than one pound per square foot, whereas one inch of wet heavy snow can reach close to 2 pounds per square foot.
However, whether it’s light and fluffy snow or heavy and wet snow, it doesn’t take long for you to accumulate a whole Toyota Prius worth of snow parked on your roof (equivalent to less than 2-inches of snow on an average-sized roof).
A 2,000 square foot roof that has 2 feet of snow, is holding approx. 48,000 pounds of snow; that’s nearly 16 Toyota Prius’s parked atop your roof! If you wouldn’t park sixteen cars on your roof, then you probably shouldn’t leave two feet of snow up there, either.
Of course, if you’ve heeded the advice I’ve given you about ice dams, that should never become an issue. To prevent ice dams you’ll need to remove the snow earlier (at least from the overhangs), after about 6 inches of accumulation, long before you are in danger of a roof collapse.
Still, if you just don’t get it done (for whatever reason) you should at least be aware of the signs of an impending roof collapse. If you see any of the below signs, be as worried as you’d be during a gas leak. Get out of the house and call a snow removal professional right away if you see any of the following:
- You see sections of your roof start to sag.
- Your ceiling starts to sag.
- You suddenly find it hard or even impossible to open doors or windows.
- You notice deformities in the roofing structure.
- You start to see cracks: in the exterior masonry, in ceilings, in the walls.
- Doors start to pop open on their own, even after you’re sure you closed them.
- You see bent or bowed pipes in your utility rooms.
- You hear creaking, popping, or cracking sounds coming from the roof or walls. This is actually a sign that a collapse is all but imminent; it means you need to get moving.
All of these signs are equally true for businesses. Business owners, whose businesses tend to have flat roofs, need to be even more vigilant than homeowners.
One more tidbit: if your gutters weren’t already cleaned and you know there is a snowstorm on the way, you need to get outside and get them cleared out. Melting snow needs somewhere to go. Clogged gutters can exacerbate ice dam formation. Of course, once the snow starts, it is too late.