# Calculating Snow Loads Per IBC 2021

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Wednesday, August 30, 2023
5:00 PM

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## Learn how to easily calculate roof snow loads for residential or light commercial projects based on IBC 2021 requirements.

Calculating snow loads is a critical aspect of structural engineering, and inaccurate assessments can pose significant threats to the safety and durability of a structure. As snow loads can vary significantly depending on location and environmental factors, it's essential to have access to reliable and precise methods to ensure the structural integrity of your designs.

Join Laurent Gérin, P.Eng., North America Engineering Team Lead, on Wednesday, August 30th, 2023 from 1 pm to 2 pm Eastern Time (ET) to learn more about the step-by-step procedures to calculate snow loads according to the requirements of the International Building Code (IBC) 2021.

We will showcase how ClearCalcs' software takes the complexity out of snow load calculations. By considering critical parameters such as ground snow load, surface roughness, building importance, roof exposure, roof pitch, and thermal condition, our calculator provides you with reliable and accurate results. Whether you're working with sloped or flat roofs, ClearCalcs simplifies the process, saving you valuable time and effort.

### In this webinar, we will cover:

• Understanding the Importance of Accurate Snow Load Calculations
• Step-by-Step Guide to Calculating Snow Loads
• ClearCalcs Snow Load Calculator: Features & Capabilities
• Worked Examples Using Snow Load Calculator in ClearCalcs

### Webinar Summary

In this webinar, Laurent Gérin discussed the importance of considering snow loads in structural design and provided insights into key factors that affect snow loads. The webinar covered topics such as ground snow load, surface roughness, roof exposure, thermal conditions, and unbalanced snow loads. Laurent also mentioned the upcoming changes in ASC 7-22 and demonstrated how to use the ClearCalcs snow load calculator.

Laurent Gérin, P.Eng., North America Engineering Team Lead, introduced the webinar and welcomed the participants. He emphasized the importance of considering snow loads in structural design and highlighted the key topics that would be covered during the webinar.

Laurent explained that the ground snow load is a critical parameter in determining the snow loads on a structure. He mentioned that the ground snow load is typically measured at weather stations across the country and correlated with snow depth measurements. Laurent also mentioned that some areas may require site-specific studies to determine the ground snow load.

#### Surface Roughness and Roof Exposure

Laurent discussed the significance of surface roughness and roof exposure in determining snow loads. He explained that surface roughness refers to the roughness of the land around the building, while roof exposure considers the presence of obstructions that can affect the amount of snow on the roof. Laurent mentioned that these factors are important considerations in snow load calculations.

#### Thermal Condition of the Building

Laurent highlighted the impact of the thermal condition of the building on snow loads. He explained that the temperature inside the building can affect the melting of snow on the roof. Laurent mentioned that buildings with warm roofs or poorly insulated ceilings may experience slower snow melting, leading to higher snow loads.

Laurent discussed the concept of unbalanced snow load, which occurs when snow accumulates unevenly on a roof. He explained that wind and sun exposure can cause unbalanced snow loads. Laurent mentioned that for rafter systems with spans less than 20 feet, the unbalanced snow load is typically applied to one side of the roof.

#### ASC 7-22 Changes

Laurent briefly mentioned the upcoming changes in ASC 7-22, the latest version of the American Society of Civil Engineers (ASCE) 7 standard. He explained that the new version includes a revised ground snow load map and adjustments to snow drift loads based on winter winds. Laurent highlighted that the adoption of ASC 7-22 by local jurisdictions may result in changes to snow load requirements.

Laurent demonstrated the use of the ClearCalcs snow load calculator. He entered the location, Mammoth Lakes, California, and selected the appropriate parameters such as ground snow load, surface roughness, roof exposure, thermal condition, and roof properties. Laurent showed how the calculator automatically calculates the flat roof snow load and sloped roof snow load based on the input parameters.

#### Designing the Rafter

Laurent used the ClearCalcs wood beam calculator to design the rafter for the calculated snow load. He selected the appropriate rafter size and adjusted the load values to match the calculated snow load. Laurent demonstrated how the calculator determines whether the rafter passes or fails based on bending, shear, bearing, and deflection criteria.

In conclusion, Laurent emphasized the importance of considering snow loads in structural design, especially in areas prone to heavy snowfall. He encouraged participants to provide feedback on the ClearCalcs snow load calculator and announced upcoming webinars on related topics.