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 determine if you may need to be concerned.

Basic calculation – (for a quick analysis only) This calculation uses a 25% moisture density which may be conservative for our current snow fall. As a rule of thumb, saturated snow weighs about 20 pounds per cubic foot. The moisture content of snow can range from about 1% to about 33% so snow can weigh from about 1 pound per cubic foot to over 21 pounds per cubic foot.
(S)(1.25)=P
S=Inches of snow on the roof
1.25= Weight of 1 sq ft of snow for each 1” of depth
P= Pounds per square foot

Example:
If my roof has 20” of snow, what would that equate to?
(S)(1.25)=P (20”)(1.25 lbs/sq ft) = 25 lbs/ sq ft
In this example the roof would be ok.
Note:  Any ice build-up on the roof needs to be added to this formula. Use 5.2 lbs for every inch in thickness.
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