Don’t worry, your roof can handle the snow
If you did any snow shoveling, you know how heavy it is. And the longer the snow sticks around, the heavier it gets because of freezing from cold overnight temperatures.
Snow can weigh as much as 10 to 25 pounds or more per cubic foot, depending on moisture content, including ice. As mostly ice, it can weigh over 50 pounds per cubic foot. On a roof, depending on the depth, it could be equivalent to a car or truck on your house.
Is your roof in danger of collapsing?
“That’s our main concern right now,” said Mark Nalesnik, Carbon County Emergency Management Agency director. “Snow absorbs moisture, making it heavier.”
Paul McArdle of Summit Hill, a roofing contractor for 52 years until his retirement a few years ago, said most people can sleep tight with nothing to worry about.
“Yes,” he said regarding whether roof snow is a danger, but that “a roof that’s been around awhile is safe.”
The biggest causes for concerns, he said, are flat roofs like those on patios. “Right now I wouldn’t want to be under one of those,” he said.
For houses, McArdle said that most roofs are supported with 2-by-8 or 2-by-6 beams, which give them a lot of support. He said houses which have had roofs on for a period of time have already endured heavy snowfalls over the years which proves them capable of handling such weight.
He said one thing to be on the lookout for is pieces of snow hanging over the edge of a roof. This can fall at any time and land on an unsuspecting passer-by.
McArdle said in most cases there isn’t much you can do about overhanging snow except be alert as a pedestrian.
Both he and the National Weather Service said it can be dangerous to go onto a roof to remove the snow and the property owners shouldn’t attempt to do so.
Nalesnik said there has been one report of a roof collapse during the recent storm. He said he understands that an old garage or small building had a roof collapse in Lansford. Although he wasn’t at the scene, he said he was informed it wasn’t a residency.
In many cases, especially with heavily slanted roofs, the snow comes off quickly, especially if the top floor of the home is heated.
Such heat doesn’t usually hit the outer foot of the roof, which generally is the overhang.
If there is enough snow to collect on the roof, the heating and melting combination can make the snow heavier because of the colder nights, which cause the precipitation to freeze.
In his career, McArdle has installed more than 2,000 roofs. He said he doesn’t feel any roof installed properly on a residence is in danger of collapse.
Another concern of snow on the roof is damming, a calamity which was widespread in the early 1900s after a heavy snow and moderate melting. The snow turned to liquid, then froze in drain pips and expanded, causing the ice to enter homes through the eaves.
Literally thousands of houses sustained water damage at that time because of the damming problem.
McArdle said even this situation generally is no longer a cause for despair.
He said that what happened was the snow would melt from sunlight, then freeze on the cold nights. When it expanded, “it had to go somewhere,” he said.
Today most roofing contractors now install snow and ice shields on the roofs they install, many as a result of that prior situation.
“People (contractors) have been doing that on the first 3 feet of the roofs,” he said. “I personally was doing the entire roof with it.” He said such snow and ice shields have been proven effective.
With snow on the roof, McArdle said, “There’s nothing you can do about it.” He said for years he, as a contractor, would climb on roofs and chipped away the ice, but by 3:30 in the afternoon, things would begin refreezing as temperatures dropped.
“I don’t think you have to worry about the snow,” he said, noting that if it has endured past storms it is built to withstand even the mammoth storm we just endured.