Trusses

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Trusses can be temporary or a permanent part of the structure.

Summary

Trusses are parts of a framework that brace or support a structure. They can be temporary or a permanent part of the structure.

When properly designed, fabricated and erected, trusses are a strong and effective way to support a structure during construction. However, if the design instructions or safety guidelines are not followed, the structure could collapse. Individual trusses can also fail if damaged during transport or installation.

Truss installation is a complex and dangerous operation. Trusses come in a variety of different shapes and sizes, and have their own set of hazards. The installation of a truss can be done in different ways with multiple types of equipment, including working around mobile cranes and bringing a risk of fall from height.

In New Brunswick, a number of truss collapses, many involving roofs, have resulted in serious or fatal injuries.

When constructing a building or structure, both the employers and contractors must ensure that:

  • Trusses and any component designed for support are installed completely, before that part of the structure carries any load. [Reg. 91-191, S. 95(1)]
  • When a building is being constructed, bracing or shoring for each floor where concrete is being poured is removed only after an engineer’s approval. [Reg. 91-191, S. 96(1)]
  • Unstable walls made of brick, concrete blocks or similar materials are braced from both sides until the wall is attached to a rigid structure and the mortar has set enough to provide the necessary support. [Reg. 91-191, S. 95]
  • Unstable walls or structures designed to support any load, including roof trusses, are braced from both sides until the wall or structure is stabilized. [Reg. 91-191, S. 95]
  • Unstable walls of reinforced steel, piers or similar structures are adequately supported to prevent the wall or structure from overturning or collapsing. [Reg. 91-191, S.95]

Employers and contractors must ensure wooden trusses are: [Reg. 91-191, S. 96.1]

  • Not erected unless the manufacturer’s directions (normally referred to as “truss installation and temporary bracing”) are available on the project site and are set up according to those directions. Manufacturer’s directions must be made available to an officer upon request.

While the employer is ultimately responsible for all the provisions mentioned above, the supervisor has a vital role to play in the safety of their teams. Supervisors must:

  • Acquaint your employees with the hazards and control measures associated with their work
  • Provide the information and instruction necessary to ensure their health and safety
  • Enforce company safety rules, programs, codes of practice and procedures, including ensuring employees comply with the requirements below.
  • Ensure that employees are competent for the tasks they perform

Truss Safety Awareness eLearning course by the New Brunswick Construction Safety Association (eLearning - NBCSA) can improve the competency of employees.

Legislation

General Regulation - Occupational Health and Safety Act

N.B. Reg. 91-191

Part X CONSTRUCTION, TRAFFIC AND BUILDING SAFETY

Section 95 Buildings and Structures
  • 95. (1) Where a building or structure is being constructed, an employer and a contractor shall each ensure that
    • (a) work is completed on any component designed to support or give added support to a part of the building or structure before proceeding with any work that adds to the load on that part,
    • (b) an unstable wall of brick, concrete blocks or similar materials is adequately braced from both sides until the wall is attached to a rigid structure and the mortar has set adequately,
    • (c) an unstable wall or structure designed to support roof components or any load is braced from both sides until the wall or structure is stabilized, and
    • (d) an unstable reinforced steel wall, pier, column or similar vertical structure is adequately supported to prevent the wall, pier, column or structure from overturning or collapsing.
  • (2) Where the framework of a building or structure is erected in advance of the outer walls, an employer and a contractor shall each ensure that a fall-protection system is used at the perimeter of each floor.

[N.B. Reg. 2010-159, s. 12; 2024-38, s. 59]

Section 96
  • 96. (1) Where a building or structure is being constructed, an employer and a contractor shall each ensure that bracing or shoring is retained at all floor levels beneath the floor where concrete is being poured until the removal of the bracing or shoring is authorized by an engineer.
  • (2) An employer and a contractor shall each provide, if requested by an officer, certification by an engineer that the forms, bracing, shoring and supports for concrete to be used in construction will safely support the intended load.
Section 96.1 Wooden Trusses
  • 96.1 (1) An employer shall ensure
    • (a) that wooden trusses are not erected unless the manufacturer's specifications for the safe erection of the wooden trusses are readily available on the project site, and
    • (b) that wooden trusses are erected in accordance with the manufacturer's specifications referred to in paragraph (a).
  • (2) An employer shall ensure that the manufacturer's specifications referred to in paragraph (1)(a)
    • (a) are kept on the project site, and
    • (b) are made available to an officer on request.

[N.B. Reg. 96-61, s. 2]