(Sept. 10, 2018) Can your roof handle the weight of solar panels? Years ago, in this area of Northern Illinois, storms piled so much snow on roofs that a few roofs actually collapsed. People were taking shovels up onto their roofs and shoveling the snow to alleviate the weight. What does this mean to you as you consider putting solar panels up on your roof? Do you need to worry about the weight?
Rest assured, the answer is, No. You don’t have to worry about the weight of solar panels on your roof.
Solar panels, including all the mounting equipment, weigh about 2- to 4-pounds per square foot. That’s the one-square-foot equivalent of putting one of the following up on your roof:
- A pineapple
- A small cat
- A two-slice toaster
- A two-liter bottle of soda
- A one-quart carton of soy milk
- A medium pumpkin
- A Pomeranian
- A bowling pin
You can put any of these items up on your roof and not worry, even for a moment, that they might plunge through the roof. But, how much weight can your roof hold? Of course, a solar energy array weighs more than a pineapple. But, the weight is distributed or should be.
According to the Insurance Institute for Business & Home Safety (IBHS), your roof should be able to support 20-pounds of snow, per square foot, before the roof is ‘stressed.’ The IBHS goes on to explain that “10-12 inches of snow is equal to … about 5 lbs. per square foot.” However, if you have “2 feet of old snow and 2 feet of new snow” (4-feet total or 60 pounds per square foot), you could have a problem since the old snow is packed and heavier. But, when is the last time you saw 4 feet of snow on your roof?
Since you don’t have to worry about the weight of your solar panels, it’s nice to know that the Office of Energy Efficiency & Renewable Energy says that snow can actually help to clean your solar panels (rain does the same thing). Of course, snow isn’t a big concern this time of year.
The real key to the question of the weight of solar panels is the distribution of weight. Properly installed, the weight is distributed across your roof to the extent that weight is never an issue. If, however, someone doesn’t install your solar panels correctly, then all bets are off and you could have trouble with your roof someday.