There is snow and there is snow. The light, fluffy stuff of February has given way to the heart-attack snow of March. And now it’s going to rain. Swell.
Last month, Reuben Saltzman at Structure Tech, who writes the Home Inspector column for the Star Tribune, did the math and said the snowfall was too light to do any damage to your roof under the state’s building requirements.
But that was then and this is now. On Monday he measured the weight of the snow in his backyard and it’s now 35-40 pounds per square foot, compared to February’s 15 pounds per square foot.
That’s significant because the building code in Minnesota requires a home’s roof to withstand 35 pounds per square foot.
He writes that he’s no longer comfortable telling people not to worry about the snow on the roof.
If you have large areas where a lot of snow drifts, you’re going to have a lot of weight concentrated in these areas. If you have a flat roof or a low-sloped roof, you have a greater potential for problems. You probably don’t need to worry about collapse… yet… but we have a lot more rain in the forecast for the rest of the week. Given the additional weight that this will add to roofs, it might be a good idea to remove snow. Today.
As I mentioned in my blog post on ice dams, using a roof rake is a good way to remove snow from the ground. Don’t risk your life walking around on your roof to shovel the snow off. If you can’t remove snow with a roof rake, hire a professional to remove the snow.
On the other hand, if you look up at your roof and you see a lot of bare shingles, or you have a very steep roof, you probably don’t have much to worry about.