Canadian building code question

What are the building code requirements for rooftop patios on commercial buildings in Canada?

Rooftop patios on commercial buildings must address structural live loads for the intended use, guard requirements at edges and openings, means of egress from the rooftop level, occupancy load calculations, and fire safety provisions including access for firefighting.

Rooftop patios on commercial buildings have become increasingly popular, but they introduce building code requirements that many project teams underestimate. The roof structure must be designed for the higher live loads of an occupied space, guards must meet height and strength requirements for the occupancy type, means of egress must serve the rooftop occupant load, and fire safety provisions must account for the additional occupied level. Weather protection, drainage, and accessibility also require attention.

What to check first

  • Structural loads must be redesigned for occupied rooftop use, which is significantly higher than standard roof loads.
  • Guard height and strength requirements depend on the occupancy classification and expected use of the rooftop space.
  • Means of egress must serve the rooftop occupant load, which may require additional exits or upgraded stair capacity.

Jurisdiction notes

Structural load requirements

An occupied rooftop patio requires live load design for assembly or the specific intended use, which is much higher than standard roof snow and maintenance loads.

Guard requirements

Guards at rooftop edges must meet the height and load requirements for the occupancy classification. Commercial rooftop patios typically require higher guards than residential balconies.

Egress from rooftop

The means of egress from the rooftop must accommodate the calculated occupant load and connect to the building's exit system.

Work through it in this order

  1. Determine the occupancy classification and expected occupant load for the rooftop patio.
  2. Verify that the roof structure can support the required live loads for the intended use.
  3. Design guards that meet the height and strength requirements for the occupancy classification.
  4. Confirm that the means of egress from the rooftop serves the occupant load and connects to the building's exit system.

Common questions

Do rooftop patios count as an additional storey?

In some code interpretations, an occupied rooftop can affect building height calculations. This varies by jurisdiction and the specific rooftop configuration.

What occupant load applies to a rooftop patio?

The occupant load depends on the intended use. Assembly use (such as a restaurant patio) will have higher occupant loads than a casual seating area.

Are rooftop patios required to be accessible?

If the rooftop is part of the building's usable space, barrier-free access requirements may apply. This depends on the building type, occupancy, and provincial code provisions.