Roof Snow Load Calculator

Calculate the weight and pressure of snow accumulation on your roof. Get instant results with visual diagrams and detailed step-by-step solutions.

Calculate Snow Load

How to Calculate Roof Snow Load

Roof snow load is a critical structural engineering calculation that determines the weight of accumulated snow on a roof surface. Understanding snow load is essential for ensuring building safety and structural integrity, especially in regions with significant snowfall. This comprehensive guide explains the calculation process step by step.

Snow Load Calculation Formulas

The key formulas for calculating roof snow load are:

\[ \text{Snow Volume} = \text{Roof Area} \times \text{Snow Depth} \]

\[ \text{Snow Weight} = \text{Snow Volume} \times \text{Snow Density} \]

\[ \text{Snow Load} = \frac{\text{Snow Weight}}{\text{Roof Area}} \]

Where:

  • Roof Area = Length × Width of roof surface (square feet)
  • Snow Depth = Depth of accumulated snow (feet)
  • Snow Volume = Volume of snow on roof (cubic feet)
  • Snow Density = Weight per cubic foot of snow (typically 15-20 lb/ft³)
  • Snow Weight = Total weight of snow (pounds)
  • Snow Load = Weight per square foot (psf)

Calculation Steps

  1. Calculate the total roof area
  2. Convert snow depth to feet
  3. Calculate snow volume
  4. Determine snow weight using density
  5. Calculate final snow load in psf

Example Calculation

Problem:

Calculate the snow load for a roof with:

  • Roof dimensions: 30 ft × 40 ft
  • Snow depth: 24 inches
  • Snow density: 15 lb/ft³

Solution:

  1. Calculate roof area:
    \[ \text{Roof Area} = 30 \text{ ft} \times 40 \text{ ft} = 1,200 \text{ sq ft} \]
  2. Convert snow depth to feet:
    \[ \text{Snow Depth} = \frac{24 \text{ inches}}{12 \text{ inches/ft}} = 2 \text{ ft} \]
  3. Calculate snow volume:
    \[ \text{Snow Volume} = 1,200 \text{ sq ft} \times 2 \text{ ft} = 2,400 \text{ cu ft} \]
  4. Calculate snow weight:
    \[ \text{Snow Weight} = 2,400 \text{ cu ft} \times 15 \text{ lb/ft³} = 36,000 \text{ lbs} \]
  5. Calculate snow load:
    \[ \text{Snow Load} = \frac{36,000 \text{ lbs}}{1,200 \text{ sq ft}} = 30 \text{ psf} \]

Snow Load Diagram

Roof Width Snow Depth Snow Load (psf)

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