Building codes are designed to make sure that roofs can withstand the usual snowfall in that area, but when should you worry that the snow on your roof is too much snow?
How much does snow actually weigh? Well, 10-12 inches (25-31 cm) of fresh snow or 3-5 inches (7-13 cm) of packed snow usually weighs about 5lbs per square foot (24.41 kilogram per square meter.) Ice is much heavier; it takes only about an inch of ice to equal the same weight.
Flat and low-sloped roofs are more vulnerable, but any roof can be damaged by heavy snow. If you see any of these warning signs, take immediate action.
- Any visible sagging of your roof
- Any unusual sounds such as cracking or popping coming from your home, especially your roof
- Roof leaks, especially new leaks. This could be a sign in stress on your roof
- If you suspect your roof or walls have had any structural damage, such as from a storm or fallen tree
If you experience any of the above, or have any reason to fear for the integrity of your roof, you should leave your home and stay someplace safe until your home has been inspected and the snow cleared.