Snow Load
14.2 PSF
Total Weight
17,076 lbs
Roof Area
1,200 ft²
Safety
Safe
Rise per 12 inches of run. Common: 4/12 (low), 6/12 (medium), 12/12 (steep)
Total Snow Load
17,076
lbs (8.5 tons)
Load per Area
14.2
PSF
Roof Area
1,200
ft²
Safety Level
Safe
5.1% slope factor
Safe
Within typical residential roof capacity
Inputs
Result
A foot of settled snow on a standard 1,200 sq ft roof creates a manageable 14.2 PSF load, well within typical residential capacity.
Inputs
Result
Two feet of packed snow creates a heavy 53.7 PSF load on a 1,750 sq ft roof, requiring attention and potential removal.
Inputs
Result
Fresh snow on a steep 10/12 pitch is very light — only 5.8 PSF due to low density and significant slope reduction.
Snow weight varies by type: fresh snow weighs about 5 lbs per cubic foot, settled snow about 15 lbs/ft³, packed snow 30 lbs/ft³, and ice 57 lbs/ft³. A foot of settled snow on a 1,200 sq ft roof weighs approximately 17,000 lbs (8.5 tons).
| Snow Type | Density (lbs/ft³) | 12" on 1,200 sq ft roof |
|---|---|---|
| Fresh powder | 5–7 | 6,000–8,400 lbs |
| Settled snow | 12–18 | 14,400–21,600 lbs |
| Packed snow | 25–35 | 30,000–42,000 lbs |
| Ice | 57 | 68,400 lbs |
Most residential roofs are designed for 20-40 PSF (pounds per square foot) snow loads, depending on local building codes. Roofs in heavy-snow regions may be rated for 60+ PSF. Check your local building codes for specific requirements.
| Region Example | Ground Snow Load (PSF) | Typical Roof Rating |
|---|---|---|
| Atlanta, GA | 5 PSF | 15–20 PSF |
| Chicago, IL | 25 PSF | 30–40 PSF |
| Boston, MA | 35 PSF | 40–50 PSF |
| Denver, CO | 30 PSF | 35–45 PSF |
| Buffalo, NY | 50 PSF | 55–70 PSF |
| Tahoe, CA | 200+ PSF | 100+ PSF |
Yes, steeper roofs experience less snow load because snow slides off more easily. The slope reduction factor equals the cosine of the roof angle. A 4/12 pitch reduces load by about 5%, while a 12/12 (45°) pitch reduces it by about 29%.
Consider removal when snow load approaches your roof's design capacity, typically above 20-30 PSF for older homes. Warning signs include creaking sounds, doors that stick, visible sagging, or cracks in walls or ceiling. Always hire a professional for roof snow removal.
Multiply the snow depth in feet by the snow density in pounds per cubic foot. For example, 12 inches (1 foot) of settled snow at 15 lbs/ft³ equals 15 PSF of ground snow load. Apply the roof slope factor for actual roof load.
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Last Updated: Mar 9, 2026
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