NBC 2025 update

What are the NBC 2025 wind and snow load changes in Canada?

The NBC 2025 revises specified wind and snow loads to use uniform risk by reducing load factors to 1.0, using 1-in-500 annual probability wind loads and 1-in-1000 annual probability snow loads, and updates climatic data tables to reflect projected future conditions.

Structural engineers and designers need to understand that the NBC 2025 fundamentally changes how wind and snow loads are specified. The move to uniform risk factors and updated probability levels means that load calculations from previous code editions may not produce compliant results. Updated climatic data tables reflecting projected future temperatures and wind pressures add another layer of change that affects every project regardless of building type.

What to check first

  • Wind and snow load factors reduced to 1.0 under a uniform risk approach.
  • Wind loads now based on 1-in-500 annual probability; snow loads on 1-in-1000.
  • Climatic data tables updated to reflect projected future conditions due to climate change.

Jurisdiction notes

National baseline

The updated load factors and climatic data are part of the NBC 2025 structural provisions and require provincial adoption.

Provincial adoption impact

Until your province adopts NBC 2025, structural designs should use the load factors and climatic data from the currently adopted edition.

Site-specific considerations

Updated climatic data may significantly change design loads in some regions, especially coastal and northern areas.

Work through it in this order

  1. Confirm which NBC edition your province currently requires for structural design.
  2. Look up the updated climatic data for your project location under the NBC 2025 tables.
  3. Recalculate wind and snow loads using the new factors and probability levels.
  4. Compare results against previous edition calculations to identify design impact.

Common questions

Do the reduced load factors mean lower design loads?

Not necessarily. The load factors are reduced but the specified loads use higher probability levels, so the net effect on design varies by location and load type.

Why did the climatic data change?

The updated tables incorporate projected future conditions rather than relying solely on historical data, reflecting the impact of climate change on wind and snow patterns.

Should I use NBC 2025 loads now?

Only if your province has adopted the NBC 2025. Use the load data from the currently adopted code edition for your jurisdiction.