This article was originally published by Lisa Egan at Tess Pennington’s ReadyNutrition.com
Tess is the author of The Prepper’s Blueprint: How To Survive ANY Disaster
There are many potential dangers associated with winter weather, but there’s one you might not have given much thought to: snow and ice on your home’s roof.
It is unclear how many deaths per year are caused by snow accumulations on roofs, but nearly every winter, there are reports of such deaths that appear in the news.
Roof collapse is a possible risk when snow accumulates on your roof, but it isn’t the only danger. In 2018, a chunk of snow about the size of a trailer fell from a roof and killed a mother and her 7-year-old son in Northern California. And, snow removal in itself carries the risk of injury and even death.
Here’s how to assess how much snow your roof can handle, how to determine if you need to remove snow, how to remove it safely, and the unique dangers that thawing ice and snow pose.
How much snow can your roof handle?
According to the Insurance Institute for Business & Home Safety (IBHS), unless your roof is damaged or decayed, it should be able to support 20 lb per square foot of snow before it becomes stressed.
These guidelines from IBHS can help you estimate how much snow is on your roof:
Fresh snow: 10–12 inches of new snow is equal to one inch of water, or about 5 lb per square foot of roof space, so you could have up to 4 feet of new snow before the roof will become stressed.
Packed snow: 3–5 inches of old snow is equal to one inch of water, or about 5 lb per square foot of roof space, so anything more than 2 feet of old snow could be too much for your roof to handle.
Total accumulated weight: 2 feet of old snow and 2 feet of new snow could weigh as much as 60 lb per square foot of roof space, which is beyond the typical snow load capacity of most roofs.
Ice: 1 inch of ice equals 1 foot of of fresh snow.
Here’s a quick method from Berlet Roofing you can use to estimate how much the snow on your roof weighs:
To check the snow load on your home, cut a 1-foot by 1-foot square the full depth of the snow from your roof into a plastic bag and weigh the bag. If there is any ice in your square foot, be sure to included it. The weight of the bag with the snow in it will tell you the weight of snow load per square foot on your roof.
Here’s a snow load calculation from Berlet Roofing:
(S x 1.25lbs)+(I x 5.2lbs) = P
S = inches of snow on the roof (depth)
1.25lbs= Approx weight of snow for each 1-inch of depth per sq ft
I = Inches of Ice Buildup on the roof (depth)
5.2lbs= Approx weight of ice for 1-inch of depth per sq foot
P =pounds per square foot (lbs/sq ft)Example: If the snow on my roof is 20-inches deep with .5 inches of ice, what would that equate to?
(20-inch roof snow depth x 1.25 lbs/sq ft ) + (.5-inch roof ice depth x 5.1lbs/sqft)= 27.1 lbs per sq ft of roof snow load.
If you are in the “danger zone” based on the thickness of the various types of snow and ice (if they exceed 20–25 pounds per square foot), you should consider removing snow from your roof.
Watch for signs that your roof is over-stressed.
Over-stressed roofs typically display some warning signs. Wood and steel structures may show noticeable signs of excessive ceiling or roof sagging before collapsing.
FEMA recommends watching for these signs:
- Sagging ceiling tiles or boards, ceiling boards falling out of the ceiling grid, and/or sagging sprinkler lines and heads
- Sprinkler heads deflecting below suspended ceilings
- Popping, cracking, and creaking noises
- Sagging roof members, including metal decking or plywood sheathing
- Bowing truss bottom chords or web members
- Doors and/or windows that can no longer be opened or closed
- Cracked or split wood members
- Cracks in walls or masonry
- Severe roof leaks
- Excessive accumulation of water at non-drainage locations on low slope roofs
Here’s how to safely remove snow from your roof.
Experts say you should never attempt to remove snow from your roof by yourself. Dangers associated with roof snow and ice removal include sliding off the roof, falling off a ladder, overexertion, and injury from sliding snow.
For safe removal that won’t endanger you or damage your roof, use a snow rake with a long extension arm that will allow you to remove the snow while standing on the ground. Climbing onto your roof to remove snow is generally not advised, as falls are a serious risk, and so is damage to the roof.
If you feel you cannot safely remove the snow yourself, consider hiring a snow removal professional.
Here are a few snow removal tips from FEMA:
- Removing snow completely from a roof surface can result in serious damage to the roof covering and possibly lead to leaks and additional damage. At least a couple of inches of snow should be left on the roof.
- Do not use mechanical snow removal equipment.
- The risk of damaging the roof membrane or other rooftop items outweighs the advantage of speed.
- Do not use sharp tools, such as picks, to remove snow. Use plastic rather than metal shovels.
- When using a non-metallic snow rake, be aware that roof snow can slide at any moment. Keep a safe distance away from the eave to remain outside of the sliding range
Be sure no one is standing or walking in the areas where falling snow and/or ice may land.
Watch for icicles and be sure they won’t fall on anyone – an icicle falling from a low height can still cause injury.
Watch for ice dams.
An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow (water) from draining off the roof. The water that backs up behind the dam can leak into a home and cause major damage to walls, ceilings, insulation, and other areas. Significant snow accumulations and extended periods of below-freezing temperatures increase the risk of ice dams developing.
“Melted snow runs down the roof under the snow cover and refreezes along overhangs where the roof surface temperature is lower. The water from the melting snow becomes trapped behind the dam of ice and can back up under shingles and infiltrate the underlayment, leading to leaks in the home,” the National Roofing Contractors Association (NRCA) explains.
Here’s a longer explanation of how ice dams form, from the University of Minnesota Extension:
There is a complex interaction among the amount of heat loss from a house, snow cover and outside temperatures that leads to ice dam formation. For ice dams to form there must be snow on the roof, and, at the same time, higher portions of the roof’s outside surface must be above 32 degrees F while lower surfaces are below 32. For a portion of the roof to be below 32, outside temperatures must also be below 32. When we say temperatures above or below 32, we are talking about average temperature over sustained periods of time.
The snow on a roof surface that is above 32 will melt. As water flows down the roof it reaches the portion of the roof that is below 32 and freezes. Voila! – an ice dam.
The dam grows as it is fed by the melting snow above it, but it will limit itself to the portions of the roof that are on the average below 32. So the water above backs up behind the ice dam and remains a liquid. This water finds cracks and openings in the exterior roof covering and flows into the attic space. From the attic it could flow into exterior walls or through the ceiling insulation and stain the ceiling finish.
There are roof and gutter de-icing kits you can buy that may help make the job a bit easier.
When the snow melts, it doesn’t necessarily mean you are out of danger.
When the end of winter approaches, the NRCA recommends checking your roof, gutters, downspouts, and drains for debris to ensure water from melting snow and ice and spring rain will properly drain from your roof:
Homeowners also should look to determine that the winter’s snow and ice has not damaged roof shingles or flashings or loosened sheet-metal openings. In addition, homeowners should check for signs of leakage around roof hatches, skylights and vents. Shingles around gutters should also be checked for damage from melting ice dams. If a roof has leakage due to ice damming, the damage should be inspected by an NRCA member contractor.
If you cannot safely evaluate your roof, experts advise hiring a roofing professional to do it for you.
Tess Pennington is the author of The Prepper’s Blueprint, a comprehensive guide that uses real-life scenarios to help you prepare for any disaster. Because a crisis rarely stops with a triggering event the aftermath can spiral, having the capacity to cripple our normal ways of life. The well-rounded, multi-layered approach outlined in the Blueprint helps you make sense of a wide array of preparedness concepts through easily digestible action items and supply lists.
Tess is also the author of the highly rated Prepper’s Cookbook, which helps you to create a plan for stocking, organizing and maintaining a proper emergency food supply and includes over 300 recipes for nutritious, delicious, life-saving meals.
Visit her website at ReadyNutrition.com for an extensive compilation of free information on preparedness, homesteading, and healthy living.
Not if you live in Western KY except for 1977 and 1978. Now you crazy Yankees are another story.
This is one of the reason we live in the Sunshine/Gunshine State.
Watch out fur dem gators and hogs!
Could it be that I have an idea that will make someone rich?
Make roof tiles that not only work as solar panels but also warm snow so that it melts into water and runs off the roof into a water catchment system.
.
It’s an old idea. At one time, there were heated sidewalks to do just that.
htt ps://en.m.wikipedia.org/wiki/Snowmelt_system
It seems like the earliest ones were in the 1950’s.
Similarly, in semi-arid paces, a fine mist is sprayed and as it drips, a dramatic drop in the roof temperature helps cool it, lowering air conditioning costs. The water gets recycled into a reservoir (with some evaporation) by a pump.
They have tried using snow melt by various systems to provide water, but 6-12 inches of snow equal 1 inch of rain plus trying to keep it operations by various means is difficult.
For kicks sometime, TRY to melt snow and accumulate any water. The problem is the low humidity plus the energy needs and produce some water that doesn’t taste scorched.
I make hot tea.
Then send the wife up on roof with shovel.
About an hour later she finishes the roof job.
Then off to the bed to warm up.
Problem solved. Everyone is now warm and happy.
Damn I love winter.
In the summer the wife will be mowing the lawn.
Don’t worry about the heat. I’ll be sipping a cold beer or three, while she mows. About an hour later she finishes mowing. Into the pool we go for a dip to cool down. Then to bed to warm up.
Summers aren’t bad either. Wife is good at mowing yard and cleaning pool.
Advice.
Don’t marry a woman who can’t be trained to:
shovel snow
mow lawn
clean pool
haul water
gardens food
keep house spotless clean
cook
breed strong children
care for children well
and do other things well.
If you marry, marry well.
You pus sy political correct weakling deserve the spoiled females you allow to run over you and your money.
My wife works two jobs. We live well. We are happy. And she does not spend over $20 without calling me for permission. My wife is the best.
FREEEEZZEEE DIRTBAG….⛄⛇⛆((POOF))I never have to worry about this problem. We’ve never had that much snow.
In the Ski Town that I lived in, the snow load requirement was 200 lbs per square foot for roofs.
I once received a call of a mass casualty incident. I arrived on scene and there were arms and legs sticking out of a pile of snow in front of a condo. The roof had over 6 feet of dense snow on it. About 8 people had lined up in front of the condo to take a group picture. They were under the roof edge that that had a big snow and ice overhang. The last guy out, that was going to take the picture, slammed the door on his way out and the roof slid on top of the group. All were injured but no one was killed and the Fire Department and Paramedics dug them out and transported them to the hospital with broken bones and bloody heads.
On another occasion I was dispatched to a Mobile Home Park for a report of an explosion. Upon my arrival there was a guy laying on a couch, dazed, in the center of the road with the front of the trailer laying in the street. It took me a while to process what I was seeing. Since it was a mobile home park, the residents have to frequently shovel their roofs because of the snow load. The year was 200% of normal for snow. The guy on the couch in the road had shoveled his roof and the snow was up to the roof on both sides of the trailer, as well as the rear. He had shoveled a 3 foot wide, 8′ deep trench to the side door. He had shoveled the snow onto the propane meter on the side of the house and broke the propane line. Propane which is heavier than air accumulated under the trailer and rose until it found an ignition source, the water heater. Since the trailer had snow on both sides, the rear and snow on the roof, the trailer was essentially a like a muzzle loading cannon. The couch was at the front of the trailer because it was the only window he could see out of.
That year several buildings blew up with some catching fire. The city changed the building code to require all propane meters to have a heavy duty structure built over them. That fixed the problem.
The most tragic case was when the roof slid at a preschool and killed a 4 year old girl playing in the school yard.
I have also seen older buildings split in half from heavy snow loads.
The 20 lb.per sq./ft.load design calculation is pure bs.
IT doesn’t take into account live loading from wind shear in addition to the fact that your roofing materials and decking are part of the equation.
Figure it like this….if you hear er crackin its time to start packin.
OR U COULD ~~~>
ht tps://youtu.be/3ESoYvkhkZo
Thermal stress is more concerning for me. Most materials do not do well with 100° temperature fluctuations in a 72 hr.period.
https://youtu.be/3ESoYvkhkZo
My roof is 2×6 it can handle 3 ft of wet heavy snow no problem. Homes in New England rarely have roof cave ins cus of snow. Buildings do though from time to time. Older homes are over built. The new homes roof trusses are 2×4 and already built and installed by crane.
The only formula that really matters is this one:
(D x M) / (F x R) = B
D = depth of snow in inches
M = minutes spent shoveling
F = temperature (outdoors) in Fahrenheit degrees
R = rest breaks (3 minutes each)
B = bottles of beer necessary for recovery
So, if it’s 30F outside and you have 6″ of snow:
[ shoveling 6″ of snow for 30 minutes = 180 ]
— now divide by:
[ 30 (degrees) multiplied by 2 rest breaks = 60 ]
— the result is 3 bottles of beer for recovery.
I just now created this formula; it seemed like an opportune time for it, since I’m in the middle of a snow & ice storm right now.
So now California is a Yankee state?
California is a corrupt Communist state.
Tyrants. Made up nonsense rules and regs. Taxes taxes taxes. Fees fees fees. More taxes and fees.
No respect for USA constitution, or for working peoples hard earned dollars.
Officials are THIEVES, corrupt, liars, no common sense.
Flee California, Out of the corrupt harlot, good people should Flee.
Many people have.
California was once part of the League of the South.
But, I can walk the dogs to the point of exhaustion, almost every day, and not see what I would consider to be a man.
Most everyone is “floaters” or gypsies, with no intention of literally settling here and colonizing this place.
You can get a snow rake for removing the snow from the areas of the roof that you can reach from the ground. Certain areas of my roof are so high up that I can’t reach them from the ground;working with a ladder in deep snow is extremely awkward.
Another factor is roof pitch.
In the South we have lower pitch (flatter) roofs.
Higher pitched roofs will shed the snow better, but they require more material$ because there is more roof 🙂
Here is what the Federales say about Snow loads. Our tax money paid for it, so give it a look for what you can learn.
ht_tps://www.fema.gov/media-library-data/7d8c55d1c4f815edf3d7e7d1c120383f/FEMA957_Snowload_508.pdf
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If you do enough work, you will start to develop your habits and style. I guess, over time, this would become it’s own culture. I have watched traditional builders, using nothing but hand tools, in colder countries. Their roofs are not made to the same codes, nor from the same modern materials, and their roofs didn’t collapse.
We are not typically allowed any creative input, or to utilize things from our own surroundings.
I have seen a video of people in Alaska taking snow off a steep pitched roof by throwing a rope over the building and using it to “saw” under the snow along the length of the ridgepole. It worked very well and no one was under the snow or up on a ladder when it all came down.