Snow Load Calculator

Calculate snow load on your roof to assess structural safety. Essential for homes in snow-prone regions.

Snow Load Calculator

Professional snow load calculator for structural engineering and building design. Calculate snow loads on roofs, analyze structural capacity, and ensure code compliance.

Structural Analysis

Code Compliance

Safety Assessment

Engineering Design

About Snow Load Calculations

Snow load calculations are critical for structural engineering and building safety. Our calculator helps determine the weight of snow on roofs, ensuring structures can safely support winter loads according to building codes and engineering standards.

Snow Load Factors

Snow Properties

Snow depth and density
Moisture content (wet vs. dry snow)
Snow type (powder, wet, ice)
Accumulation patterns
Duration and age of snow

Structural Factors

Roof pitch and geometry
Roof material and condition
Building height and exposure
Wind effects and drift
Thermal effects and melting

Building Code Standards

ASCE 7

American Society of Civil Engineers standard

IBC

International Building Code requirements

Local Codes

Regional and municipal requirements

Calculation Methods

Basic Snow Load

Ground snow load (psf)
Roof exposure factor (Ce)
Thermal factor (Ct)
Importance factor (Is)
Slope factor (Cs)

Drift Loads

Windward and leeward drifts
Step and valley drifts
Parapet and wall drifts
Adjacent roof drifts
Sliding snow loads

Frequently Asked Questions

How do I calculate snow load on my roof?

Snow load is calculated using ground snow load, roof exposure factor, thermal factor, importance factor, and slope factor. The basic formula is: Snow Load = 0.7 × Ce × Ct × Is × Pg × Cs, where Pg is the ground snow load in psf.

What's the difference between wet and dry snow?

Wet snow is denser (15-30 lbs/ft³) and heavier than dry snow (5-15 lbs/ft³). Wet snow creates higher loads and is more dangerous for structures. The moisture content significantly affects the total weight on the roof.

How does roof pitch affect snow load?

Steeper roofs (pitch > 30°) allow snow to slide off more easily, reducing load. Flat roofs (pitch < 5°) retain all snow. The slope factor (Cs) accounts for this effect, with values ranging from 0.0 to 1.0 based on roof pitch.

What are snow drift loads?

Snow drifts occur when wind deposits snow in specific areas, creating localized loads much higher than uniform snow loads. Common drift locations include roof steps, parapets, and areas adjacent to taller structures.

How do I find my area's ground snow load?

Ground snow loads are provided in building codes and engineering references. Check ASCE 7 maps, local building departments, or engineering handbooks. Values range from 0 psf in warm climates to 100+ psf in mountain regions.

What safety factors should I use?

Building codes specify minimum safety factors (typically 1.5-2.0) for snow loads. Higher factors may be required for critical structures or unusual conditions. Always consult local building codes and engineering standards.

How often should I check snow loads?

Monitor snow accumulation during winter storms, especially for flat or low-pitch roofs. Remove snow when loads approach design limits. Consider installing snow guards or heating systems for problem areas.

What if my roof exceeds design loads?

If snow loads exceed design capacity, immediately remove snow from the roof. Contact a structural engineer to assess the situation. Consider temporary shoring or evacuation if structural integrity is compromised.