Snow Load

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Snow Load API

Calculate balanced and unbalanced snow loads per ASCE 7-16 and ASCE 7-22 Chapter 7.

Overview

The Snow Load API calculates:

• Flat roof snow load (p_f) - Snow load on flat roofs
• Sloped roof snow load (p_s) - Balanced snow load on sloped roofs
• Design roof snow load - Maximum of p_f and minimum snow load
• Rain-on-snow surcharge - 5 psf surcharge where applicable
• Snow drift loads - Drift loads on lower roofs and at projections

New to the API? Start with the Quick Start to run your first calculation.

Standards

Two ASCE 7 standards are supported:

Standard	Endpoint	Key Differences
ASCE 7-16	/v1/snow-load/asce7-16/calculate	Thermal conditions as numeric codes (1-6)
ASCE 7-22	/v1/snow-load/asce7-22/calculate	Descriptive thermal conditions, roof R-value input

Single-Call Endpoint

Each standard has a dedicated calculate endpoint:

Code
 
POST /v1/snow-load/asce7-16/calculate
POST /v1/snow-load/asce7-22/calculate

Both endpoints:

• Create a calculation sheet
• Apply your input parameters
• Solve and return results
• All in a single request

Response Format

All calculation endpoints return:

Code
 
{
  "sheetId": "uuid",
  "name": "Snow Load - 7-22",
  "standard": "ASCE 7-22",
  "status": "solved",
  "results": {
    "passed": true,
    "outputs": {
      "pF": 24.99,
      "pS": 24.99,
      "pDesign": 24.99,
      "unbalGeneral": 20.7,
      "unbalGeneralWidth": 9.25,
      "sdProjPressure": [],
      "sdLowerPressure": []
    }
  },
  "inputs": {
    "standard": "ASCE 7-22",
    "roofSlope": "4:12",
    "eaveToRidgeDistance": "30 ft",
    "exposure": "Partially Exposed",
    "thermalCondition": "All other structures"
  }
}

Output Fields

Field	Description	Unit
pF	Flat roof snow load (p_f)	psf
pS	Sloped roof snow load (p_s)	psf
pDesign	Design roof snow load	psf
unbalGeneral	Unbalanced snow load	psf
unbalGeneralWidth	Width of unbalanced load zone	ft
sdProjPressure	Projection drift loads (array)	-
sdLowerPressure	Lower roof drift loads (array)	-

Design Standards

• ASCE 7-16: Minimum Design Loads and Associated Criteria for Buildings and Other Structures (2016)
• ASCE 7-22: Minimum Design Loads and Associated Criteria for Buildings and Other Structures (2022)

Both standards follow Chapter 7: Snow Loads.

Units

Parameter	Unit
Ground snow load (p_g)	psf
Roof snow loads (p_f, p_s)	psf
Eave-to-ridge distance (W)	feet
Drift dimensions	feet
Roof slope	ratio (e.g., 6 for 6:12)

Project Defaults

By default, the calculator uses project defaults for:

• Risk category
• Ground snow load
• Ground surface roughness

Set overrideDefaults: true to provide these values directly. See Attributes for details.