Should I shovel the snow off my roof?
For those of you that are wondering “When should I shovel the snow off my roof?” Here is a quick rule of thumb to help you if you are concerned.
Basic calculation – (for a quick analysis only) This calculation is based on a 25% moisture density which may be conservative for our current snow fall. As a rule of thumb, saturated snow weighs approximately 20 pounds per cubic foot. The moisture content of snow can range from approximately 1% to 33%, which relates to snow potentially weighing from 1 pound per cubic foot to over 21 pounds per cubic foot.
Calculation: S x 1.25 = P where:
S = Inches of snow on the roof (depth)
1.25 = Weight of 1 sq ft of snow for each 1-inch of depth
P = Pounds per square foot (lbs/sq ft)
Example: If the snow on my roof is 20-inches deep, what would that equate to?
20-inch roof snow depth x 1.25 lbs/sq ft = 25 lbs per sq ft of roof snow load
In this example the roof would be ok.
NOTE: Any ice build-up on the roof would need to be added to this formula. Add 5.2 lbs for each 1-inch of ice depth. You can always check your roof snow load by cutting a 1-foot x 1-foot square the full depth of the snow from your roof and weighed in a plastic bag to determine if your snow load is getting close to the design roof snow load of 40 lbs per square foot. This would need to include any roof ice build-up also.
This info I found on the web. It is simple and helpful But I could not find the author to give them credit. So whoever posted this thank you.