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OBC DIVISION B · PART 3 · SECTION 3.17 — DEMOUNTABLE STAGES AND SUPPORT STRUCTURES

What engineering is required for demountable stages and support structures in Ontario?

Regulated demountable stages must be designed by a professional engineer for all applicable loads, performers and crowds, equipment and rigging loads, and especially wind, with documented erection procedures, anchorage or ballast design, and a defined operational wind management plan.

Code reference
Demountable stages and support structures regulated under Section 3.17 must be structurally designed by qualified professionals for the gravity, environmental and rigging loads they will experience, including wind on roofs, banners and video surfaces, with the design addressing foundations, ballast or anchorage, connections between demountable components, and the conditions under which the structure may be safely occupied and operated.
OBC Division B, Section 3.17 (Demountable Stages and Demountable Support Structures)

Paraphrased for clarity — open this provision in the BUILDAiD Library for the exact wording.

What this means in practice

Wind is the killer load for stage roofs: large fabric canopies and video walls act as sails, and most documented collapses involve wind on structures whose ballast or guying did not match design assumptions. The engineering package should cover not just the assembled structure but the erection sequence, ballast weights actually deliverable on site, and an operational management plan specifying wind speeds at which banners come down and the structure is evacuated. Field substitutions of components from different manufacturers are a recurring cause of failure and void the design.

Plain language

A big event stage must be designed by an engineer for everything it will face, the weight of gear and people, and especially wind grabbing the roof like a sail. The plan also says exactly when to clear the stage if winds pick up.

Related questions

When does the Ontario Building Code apply to demountable event stages?Are guards required on the edges of temporary stages in Ontario?What inspections are required for demountable stages in Ontario?

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This page is provided for general information. Building code requirements depend on your specific project, occupancy and municipality, and code editions change. Always verify requirements against the current Ontario Building Code and confirm with your local building department.