How much does snow on a roof weigh?
Short answer
A foot of fresh, fluffy snow weighs about 5 lb per square foot, but a foot of wet, heavy snow can reach 21 lb, according to FEMA. Old packed snow weighs nearly three times as much per inch as fresh, and an inch of ice almost 5 lb per square foot. On a 30 × 40 ft house, a foot of fresh snow is about 3.4 tons.
Work it out for your numbers
Snow load
5.7 lb per sq ft
- Total weight on the roof
- 6,807 lb
- In tons
- 3.4 tons
- Roof footprint
- 1,200 sq ft
Snow weight on a 30 × 40 ft roof
| On the roof | Pounds per sq ft | Total weight |
|---|---|---|
| 12 in of fresh snow | 5.7 | 3.4 tons |
| 24 in of fresh snow | 11.3 | 6.8 tons |
| 12 in of old, packed snow | 15.6 | 9.4 tons |
| 1 in of ice | 4.75 | 2.85 tons |
| 12 in fresh on top of 6 in packed and 1 in of ice | 18.2 | 10.9 tons |
Typical figures for a 1,200 square foot roof footprint. Fresh snow varies a lot: FEMA puts a foot of it anywhere from 3 lb per square foot for light, dry powder to 21 lb for wet, heavy snow.
How much can my roof hold?
It depends on where you live. Building codes set a design snow load for each area, and roofs in snowy regions are built for far more than a light dusting. Your local building department can tell you the figure for your town. Older roofs, and ones with damaged or undersized framing, can hold less than today’s code.
Warning signs of too much weight
FEMA lists signs that a roof is overstressed:
- Sagging ceilings or roof lines
- Popping, cracking or creaking sounds
- Doors or windows that suddenly stick or won’t close
- Cracks in walls or masonry, or cracked wood framing
- Severe leaks
If you see these, get everyone out and call a professional.
Clearing it safely
- Use a roof rake from the ground. Don’t climb onto a snowy roof.
- Leave an inch or two of snow so you don’t tear up the shingles.
- Watch for power lines, and stay clear of where the snow will slide off.
- For a big or steep roof, hire a pro.
Common questions
How much does a foot of snow weigh on a roof?
About 5 to 6 lb per square foot if it’s fresh and fluffy, but up to 21 lb if it’s wet and heavy. On a 1,200 square foot roof, a foot of fresh snow is about 3.4 tons.
How much does an inch of ice weigh?
A little under 5 lb per square foot.
When should I clear snow off my roof?
When it builds up beyond what your area normally gets, after heavy wet snow or rain on snow, or if you see any warning signs like sagging or sticking doors.
Sources
Updated October 29, 2026. Figures are estimates for planning. Check product labels and local codes before you buy or build.