❄️ Roof Snow Load Calculator
Estimate how much weight snow is putting on our roof using depth, density, and roof type. Based on real engineering principles used in U.S. building standards like ASCE.
🏠 What is Roof Snow Load?
Roof snow load is the weight of snow accumulated on our roof, measured in pounds per square foot (psf).
Even small amounts of snow can become dangerous depending on moisture content. 10–12 inches of wet snow can create a very heavy load, while light snow remains relatively safe.
Wet snow can weigh up to 5× more than light snow, which is why roof collapses often occur after melting and refreezing cycles.
⚙️ How This Calculator Works
- Enter snow depth
- Select snow type (density)
- Tool converts depth → load (psf)
- Applies roof adjustment factor
- Displays final structural load
Formula: Roof Load = Depth × Density × Roof Factor
🧊 Snow Density and Load Conversion
| Snow Type | Weight per Inch | Risk |
|---|---|---|
| Light Snow | ~1 psf | Low |
| Packed Snow | 2–3 psf | Moderate |
| Wet Snow | 3–6 psf | High |
| Ice | 5–7 psf | Very High |
Example: 12 inches wet snow × 5 = 60 psf
⚠️ Roof Snow Load Risk Levels
Below 20 psf → Safe
20–30 psf → Normal
30–40 psf → Stress
40–60 psf → High Risk
60+ psf → Dangerous
🧮 Manual Calculation
Load = Depth × Density
Example: 10 × 5 = 50 psf (High Risk)
❄️ Safety Tips
- Remove snow above 30–40 psf
- Watch for sagging ceilings
- Listen for cracking sounds
- Check doors/windows sticking
- Use roof rake instead of climbing
FAQs
Most residential roofs are designed for 20–30 psf.
Wet snow can weigh 3–6 psf per inch.
When load reaches 30–40 psf.