When do I need a Professional Engineer stamp in Ontario?

In Ontario, a Professional Engineer (P.Eng. licensed by PEO) must prepare, review, and seal any design that affects public safety. For buildings under the Ontario Building Code, this includes: structural drawings for buildings exceeding certain thresholds, alterations to load-bearing elements, foundations for major structures, and all post-disaster buildings. The Ontario Building Code Act (S.O. 1992, c.23) and the Professional Engineers Act (R.S.O. 1990, c.P.28) together define when P.Eng. involvement is mandatory.

What is the relationship between the OBC and the NBC in Ontario?

The Ontario Building Code (O.Reg 332/12 under the Building Code Act) is Ontario's adopted building standard. It incorporates the National Building Code of Canada 2015 by reference with Ontario amendments, and is currently in transition toward the 2020 NBC-based update. For structural design, the OBC's Part 4 (Structural Design) adopts NBCC loads and CSA material standards (A23.3 for concrete, S16 for steel, O86 for timber, S304 for masonry). Engineers must follow the OBC and the referenced CSA standards.

What professional engineering body governs structural engineers in Ontario?

Professional Engineers Ontario (PEO) licenses and regulates engineering practice in Ontario under the Professional Engineers Act. Structural engineers in Ontario must hold a P.Eng. license from PEO to offer structural engineering services and to seal drawings. PEO enforces standards of practice, continuing professional development (CPD), and professional liability requirements.

What are CSA structural standards?

CSA (Canadian Standards Association) publishes the material design standards referenced by the OBC: CSA A23.3 (Design of Concrete Structures), CSA S16 (Design of Steel Structures), CSA O86 (Engineering Design in Wood), and CSA S304 (Design of Masonry Structures). These standards are the Canadian equivalents of ACI 318, AISC 360, NDS, and TMS 402 used in the USA. Ontario engineers must use the CSA editions referenced by the current OBC.

How long does it take to get a building permit in Toronto?

Toronto building permit timing depends on the project type, submission completeness, review path, and current municipal workload. Complex projects often require multiple review rounds, so owners are best served by having their engineer or permit consultant confirm the current process and service standards with Toronto Building before filing.

Complete Guide to Structural Engineering for Ontario Property Owners

Structural Engineering| 7 min read|April 2026 · By Asvakas Engineering

What Is Structural Engineering?

Structural engineering is the branch of civil engineering concerned with the analysis, design, and inspection of load-bearing systems — the bones and sinews that allow buildings, bridges, and infrastructure to safely resist gravity, wind, seismic, and other forces. In Ontario, structural engineers design and review all elements of the building frame: foundations, columns, beams, slabs, walls, and connections.

Structural engineers in Ontario hold the P.Eng. designation issued by Professional Engineers Ontario (PEO) under the Professional Engineers Act (R.S.O. 1990, c.P.28). The P.Eng. license is required to seal any drawing or report that affects public safety — including all structural drawings filed with municipal building departments.

CSA Standards & the Ontario Building Code

Ontario's structural design is governed by the Ontario Building Code (O.Reg 332/12 under the Building Code Act, S.O. 1992, c.23). The OBC's Part 4 (Structural Design) adopts the loads and structural requirements of the National Building Code of Canada (NBC), currently transitioning to the NBC 2020 edition, with Ontario-specific amendments.

Material design standards are the CSA (Canadian Standards Association) series, referenced by the OBC:

Material	CSA Standard	US Equivalent
Structural Concrete	CSA A23.3	ACI 318
Structural Steel	CSA S16	AISC 360
Timber / Wood	CSA O86 (Engineering Design in Wood)	NDS
Masonry	CSA S304	TMS 402
Aluminum Structures	CSA S157	AA ADM1

Types of Structural Systems

Structural Steel

Steel is the dominant structural system for mid-rise and high-rise buildings in Toronto. Moment-resisting frames, braced frames, and composite (steel + concrete) systems are designed per CSA S16. Toronto's mid-rise mixed-use developments frequently use structural steel for floor framing with post-tensioned or conventionally reinforced concrete slabs.

Reinforced & Post-Tensioned Concrete

Cast-in-place concrete is the dominant system for high-rise residential towers in Toronto — the shear wall core combined with flat-plate slabs is the standard typology for 20–80 storey residential buildings. CSA A23.3 governs all concrete design including flat plates, shear walls, and transfer structures. Post-tensioned slabs (designed per CSA A23.3 Annex A) are common for long spans and reduced slab thickness.

Mass Timber

Cross-Laminated Timber (CLT) and Glued Laminated Timber (Glulam) are growing rapidly in Ontario following the 2015 OBC amendment allowing mass timber buildings to 6 storeys, and the 2020 NBC provisions for tall wood buildings up to 12 storeys (Encapsulated Mass Timber Construction). CSA O86 governs timber design.

When Do You Need a Structural Engineer?

All new building construction requiring a building permit
Renovations involving removal or alteration of load-bearing walls, columns, or beams
Adding floors, mezzanines, or significant floor loads to existing buildings
Foundation work: underpinning, new footings, helical piers
Excavation within 1.5× the depth of adjacent foundations (OHSA Reg 213/91)
Post-incident assessment: after fire, flood, vehicle impact, or unexpected cracking
Pre-purchase structural due diligence for commercial and investment properties

The Engineering Process

Structural engineering in Ontario follows a standard design progression:

Concept/Schematic Design: System selection, preliminary sizing, coordination with architecture and MEP
Design Development: Structural analysis, member sizing, connection philosophy
Construction Documents: Stamped structural drawings and specifications suitable for permit and construction
Permit Review: Toronto Building (or other municipal building department) reviews for OBC compliance
Construction Administration: Shop drawing review, RFI responses, site observation visits, Architect/Engineer coordination
Field Review: PEO's Guidelines for Professional Engineers Providing Structural Field Review — engineers must confirm as-built conditions conform to stamped drawings

Professional Engineers Ontario (PEO)

PEO is the self-regulatory body that licenses and governs all engineers in Ontario under the Professional Engineers Act. PEO's Practice Bulletins provide guidance on: independent structural design reviews, non-building structures, field review obligations, and engineering judgment. The Association of Professional Engineers of Ontario v. Lutz provisions establish that practicing structural engineering without a P.Eng. license in Ontario is a provincial offence.

Building Permits in Toronto & Ontario

Toronto uses the IBMS (Integrated Business Management System) for permit applications. Structural drawings — sealed by a PEO-licensed P.Eng. — are submitted as part of the complete application. Toronto Building reviews permit applications against the OBC and zoning by-laws, and the actual timeline depends on the project class, submission completeness, and the number of review cycles required.

Frequently Asked Questions

When do I need a P.Eng. stamp in Ontario?

For any structural design affecting public safety — new buildings requiring permits, alterations to load-bearing elements, foundation work, and post-disaster assessments. The Professional Engineers Act requires a P.Eng. license for any person providing structural engineering services in Ontario.

What is the relationship between the OBC and the NBC?

The Ontario Building Code adopts the National Building Code of Canada by reference with Ontario amendments. Structural design follows OBC Part 4, which references NBCC loads and CSA material standards (A23.3, S16, O86, S304).

What is PEO?

Professional Engineers Ontario is the licensing and regulatory body for engineers in Ontario under the Professional Engineers Act. All engineers providing services in Ontario must hold a P.Eng. from PEO.

How long do Toronto building permits take?

Toronto permit timing depends on the type of application, whether the package is complete at intake, and how many review comments must be resolved before issuance. Complete, well-coordinated submissions prepared by qualified professionals reduce avoidable review cycles.

Structural Engineering Services Across Ontario

Asvakas Engineering's PEO-licensed P.Engs. provide full structural design, field review, and CA services for buildings across Toronto and Ontario.

Request a Consultation