This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations and should not be used as or considered legal advice. Health and safety inspectors apply and enforce these laws based on the facts they find in the workplace.

Definition of “constructor”

The intent of the Occupational Health and Safety Act (OHSA or the Act) is to have 1 person with overall authority for health and safety matters on a project. This person is the constructor of the project.

Section 1 of the OHSA defines “constructor” as “a person who undertakes a project for an owner and includes an owner who undertakes all or part of a project by themself or by more than 1 employer”. A person “undertakes” a project if they assume responsibility for it. The definition of “employer” in section 1 of the Act includes contractors and subcontractors that employ workers or contract for the services of workers. “Project” is also defined in section 1 of the Act.

Health and safety at a project are a shared responsibility. Though each employer at a project has significant responsibilities for the health and safety of their workers, the constructor is the party with the greatest degree of control over health and safety of the entire project and is ultimately responsible for the health and safety of all workers. The constructor must ensure that all the employers and workers on the project comply with the Act and its regulations.

Definition of “owner”

Section 1 of the Act defines “owner” as including:

  • a trustee, receiver, mortgagee in possession, tenant, lessee, or occupier of any lands or premises used or to be used as a workplace
  • a person who acts for or on behalf of an owner as an agent or delegate

Examples where the owner is the constructor

Every project that is governed by the Act has both an owner and a constructor. The constructor will either be the owner of the project or a third party contracted by the owner to undertake the project for the owner.

Except as prescribed, and subject to the conditions and limitations prescribed, the Act does not apply to work performed by the owner or occupant, or a servant of the owner or occupant, when carried out to, in or about a private residence or the lands and appurtenances used in connection with that residence (subsection 3(1) of the OHSA).

An owner who hires an architect, professional engineer or other person solely to oversee the quality control of the work at a project does not necessarily become a constructor (subsection 1(3) of the OHSA). Such an owner could hire a third party as a constructor as well as the person engaged only to oversee the quality control of the project.

The following examples illustrate some common situations for all owners of projects, including homeowners.

When an owner hires only 1 contractor to do all the work on a project, that contractor is undertaking the work and is the constructor. This contractor is often referred to as the general contractor.

  • In the situation above, the general contractor may subcontract some or all the work to another party. They remain the constructor for the project, as long as they are the only party with whom the owner contracts to undertake the project.
  • In the situation above, if the owner is an employer who assigns their workers to work on the same project as the general contractor, they may become the constructor if the general contractor was not informed of and did not agree to the presence of the owner’s workers and does not exercise control over them. However, if the general contractor agrees to use the owner’s workers and to direct their work, they will remain the constructor.

When an owner undertakes a project by contracting with more than 1 contractor, the owner could become the constructor if no general contractor has been retained and the separate contractors work at the same time.

  • When an owner contracts with more than one contractor, the owner may enter into a contractual agreement with one of these contractors, or a third party, to undertake the project on behalf of the owner. Provided the owner has relinquished control over the project and the contractor or third party has assumed control, that contractor or third party is the constructor, even if the owner is paying the other contractors on the project.
  • Depending on the circumstances, if an owner contracts with more than one contractor but there is no agreement that one contractor accepts the constructor role, the owner will likely be deemed the constructor for the project. 
  • An owner may submit a Request for Designation of Separate Projects to the ministry. If the request is approved by a Ministry of Labour, Immigration, Training and Skills Development (MLITSD) Director, each project that is designated as “separate” would have its own constructor.
  • A Designation of Separate Projects will be a case-by-case basis and will have project specific conditions that must be met and maintained.

In summary, on all projects, either the owner or someone hired by the owner is the constructor. Everyone involved with a construction project should be clear on who is undertaking the project, meaning who the constructor is, and the responsibilities of all the parties associated with the project. It is important to put this information in writing so that the parties understand and follow the agreement.

Key duties of a constructor

Constructors have the following key responsibilities, on the projects that they undertake:

  • ensure that the measures and procedures prescribed by the Act and its regulations are carried out on the project
  • ensure that every employer and every worker working on the project complies with the Act and its regulations
  • ensure that the health and safety of workers on the project is protected
  • ensure, when and if required, that a health and safety representative or a joint health and safety committee is selected or established, when and as required
  • ensure, when and if required, that the MLITSD is notified of a project, when and as required
  • ensure that the MLITSD is notified of an accident, fatality or occurrence, when and if required by the Act (sections 51, 52, 53 and 53.1)
  • ensure that every contractor or subcontractor receives a list of all designated substances present at the project before the prospective contractor or subcontractor enters into a binding contract for the supply of work on the project
  • ensure that written emergency procedures are established for the project and posted, and
  • appoint a supervisor for every project at which 5 or more workers will work at the same time.

For a more information about constructor duties, please refer to the Occupational Health and Safety Act and the Regulation for Construction Projects (O. Reg. 213/91). Constructors who are also employers, and constructors who are also owners, have other duties under the Act and its regulations that must be fulfilled.

Relationship of the constructor to the other parties on a project

The constructor has overall responsibility on a project for compliance with the Act, the Regulation for Construction Projects (O. Reg. 213/91) and other applicable regulations. The constructor may also have duties as an employer or as an owner.

The extent of a project

Individual projects are typically identified by:

  • their location
  • the owner of the project
  • the time frame for construction activities to be undertaken by the identified constructor at that particular location

However, MLITSD inspectors will assess who the constructor is based on the facts they find at a project where they are enforcing the OHSA and its regulations.

Typically, construction activities taking place at one address owned by a person during a set period of time with an identified goal are considered a single project, which would have an owner and constructor (who may or may not be the same as the owner).

Examples of a person within the context of the above are:

  • an individual
  • a group of individuals
  • a partnership
  • a corporation

Examples of identified goals within the context of the above are:

  • erecting a new building
  • doing repairs
  • structural maintenance
  • addition or demolition of an existing structure

If you need help with the interpretation of the legislation and its potential application in your specific circumstances, contact a lawyer.

Designating separate projects

According to section 4 of O. Reg. 213/91, the owner of  a project may ask a director at the MLITSD to designate part of a project as a separate project for the purposes of the Act and the regulation.

Each designated project would have its own separate constructor. The director, in considering such a request, would look at the possibility for separating the construction activities, either in space or in time.

The director would consider spatial factors, such as:

  • independent access and egress and 
  • availability of toilets and wash-up facilities
  • whether clear boundaries exist among the various projects requested to be identified as separate
  • how much control each potential constructor for each project would have over the construction activities carried out on that project, independently from other projects
  • how much control each potential constructor for each project would have over the health and safety of the workers on that project, independently from the other projects

Each one of the separate projects would have its own joint health and safety committee or health and safety representative, when and as required, independently from the other project or projects.

Construction activities taking place at the same address, with 1 owner, may be considered separate projects when the activities are clearly separated in time.

For example, demolishing an old structure and erecting a new one could be undertaken as 2 separate projects:

  • Project A (demolishing the old building and removing the resulting debris) undertaken by constructor C1
  • Project B (erecting a new structure) undertaken by constructor C2

In this case, Project B starts only after the completion of Project A. If there was any overlap in time between the 2 projects, the owner would have to apply to a director of the MLITSD to designate them as separate projects.