Canadian building code question

What occupancy classification applies to a mixed-use building in Canada?

Mixed-use buildings contain multiple occupancy classifications, and the code requires fire separation between different occupancies, with construction type and egress requirements driven by the most restrictive occupancy. The approach depends on whether the occupancies are separated or non-separated.

Mixed-use buildings — residential over retail, office over parking, commercial with daycare — are common in Canadian development and one of the most complex code compliance scenarios. The building code does not create a single mixed-use classification. Instead, each occupancy is classified separately and the fire separation, construction type, and egress requirements are determined by the relationship between occupancies. Confirm each occupancy first, then work through the separation and construction type implications.

What to check first

  • There is no single mixed-use classification — each occupancy in the building is classified separately.
  • Fire separation between different occupancies is determined by the occupancy types and whether the building uses a separated or non-separated approach.
  • Construction type and height limits are generally governed by the most restrictive occupancy in the building.

Jurisdiction notes

National baseline

Check NBC Part 3 for occupancy classification, fire separation between occupancies, and the separated vs. non-separated building approach.

Construction type determination

The most restrictive occupancy typically governs the construction type. Verify height and area limits for each occupancy and the combined building condition.

Provincial adoption check

Some provinces have specific guidance or amendments for common mixed-use conditions like residential over commercial.

Work through it in this order

  1. Classify each occupancy in the building separately by group and division.
  2. Determine whether the building will use a separated or non-separated approach to mixed occupancies.
  3. Check fire separation requirements between each pair of occupancies.
  4. Verify construction type, height, and area limits based on the most restrictive occupancy, and confirm egress provisions for each occupancy.

Common questions

What is the difference between separated and non-separated mixed occupancies?

In a separated approach, fire separations between occupancies allow each to be evaluated independently for height and area. In a non-separated approach, the most restrictive occupancy governs the entire building.

What fire separation is required between residential and commercial occupancies?

The required fire separation depends on the specific occupancy groups and divisions involved. The code specifies separation ratings for different occupancy pairs.

Does the most restrictive occupancy always govern construction type?

Generally yes, but the separated approach can modify how height and area limits are applied. Verify the applicable method for the project.