Can Ice Dams Collapse My Roof?
It’s not an everyday occurrence, but it happens more frequently than most people realize: Ice and snow can and often do cause rooftops to collapse. That’s one reason I get so concerned whenever I drive past homes where homeowners seem oblivious to the three-feet-thick block of ice on their roof.
A potential roof collapse is another great reason for homeowners to rake their roof after any serious snow. The combination of snow and ice is more likely to cause a collapse than ice alone or snow alone.
Disastersafety.org notes that most roofs can sustain about 20 pounds per square foot before there’s any danger of a collapse (this estimate varies from state to state). Personally, I don’t think I’d take that chance. You won’t go up there with a scale and a carpenter’s square just so you can say, “Gee, this square foot of the roof has 19.2 pounds – wonder if we’re OK?” Ice and snow are heavy, period. That’s only about 4 or 5 feet of fresh snow before you roof starts crying for mercy. Old, compacted, waterlogged snow is even heavier. 4 or 5 feet of fresh snow could be equivalent to only a foot of old, packed-down snow. Of course, from the outside it all just looks like a normal snowy roof, even if it’s under serious strain.
Don’t assume the absence of a leak means you’re safe. You can have too much snow and ice on your roof and not develop any leaks at all.
There have been collapses recently. There was one at an ice rink in Canton, Massachusetts, in February of 2015. That was particularly frightening because there were kids inside. I suspect the powers-that-be shrugged and thought, “Oh, it’s just some snow,” as do so many other people I meet.
Ice Dam Guys® was even involved in trying to deal with a fairly famous roof collapse. I count it among our “coolest calls” ever.
If you’re a Minnesotan you may remember when the roof of the Metrodome caved in. Well, Yours Truly offered a plan to save the roof before it fell down. Of course, the city officials didn’t go for it, so they let it collapse and wasted money putting on a new roof. Our plan would have absolutely worked – but that’s a whole nother story. (To this day, I still believe that’s the outcome they wanted.)
Anyway, back to your roof, which you want to keep in piece.
There are some things you can look for if you want to check whether your roof is in danger of collapsing. Of course, if your roof looks to be straining or sagging you might want to call an ice dam removal professional. Most ice dam removal companies (including us) also provide rooftop snow removal services.
If you hear creaking and popping you’ll want to call an ice dam pro immediately.
Do you have to tug on the door to open it, or wrestle it closed? That could mean the weight on your roof has put extra pressure on your door-frame. The same may apply to your windows, if they’re difficult to open or close.
People have died in these collapses, to say nothing of the damage to your home and personal property. Even if none of the above appear to be an issue, don’t take chances. Get those multi-ton blobs of snow and ice off your roof.