Structural Peer Review in Ontario: When It's Required & What to Expect

What Is Structural Peer Review?

A structural peer review is an independent technical assessment of a structural engineering design — drawings, calculations, specifications, and geotechnical recommendations — conducted by a qualified structural engineer who played no role in the original design. The purpose is to provide an independent check that the design: (1) complies with Ontario Building Code, NBCC 2020, and applicable CSA structural standards; (2) correctly identifies and applies all relevant loads; (3) adequately sizes all structural members, connections, and foundations; and (4) addresses the specific risks of the project type and site.

Peer review is not a duplication of the building department's plan review. Municipal plan reviewers confirm code compliance at a high level and verify permit documentation; the engineering peer reviewer performs a detailed technical engineering assessment at the same depth as the original engineer of record.

When Is Peer Review Required in Ontario?

Ontario does not have a single province-wide trigger for mandatory structural peer review. Requirements come from several sources:

• Municipal discretion (Building Code Act s.8): The Chief Building Official (CBO) may require additional information or technical review as a condition of permit issuance where the proposed construction is complex, novel, or represents a public safety risk. Larger Ontario municipalities — particularly the City of Toronto — exercise this authority broadly for mid-rise and high-rise buildings.
• Special-purpose buildings: Schools (Ministry of Education directives), hospitals (Ministry of Health capital planning requirements), and post-disaster buildings may require peer review as a project approval condition from the commissioning ministry or authority.
• Complex or novel structural systems: Long-span structures, transfer floor systems, deep excavations, unusual lateral systems, and base-isolated buildings typically attract peer review requirements both from municipalities and from institutional owners' project controls.
• Seismic risk in eastern Ontario: Projects in Ottawa and eastern Ontario — areas with meaningful seismic demand under NBCC 2020 — may attract voluntary or required peer review of seismic design, particularly for post-disaster buildings or irregular structures.
• Lender/insurer requirements: Construction lenders financing large development projects sometimes require peer review as a risk management condition of project financing.

City of Toronto Peer Review Requirements

The City of Toronto has the most developed peer review program among Ontario municipalities. Toronto Building routinely exercises its authority under the Building Code Act to require independent structural review for:

• Buildings over approximately 8–10 storeys (the threshold varies by structural system and complexity)
• Complex foundation systems including deep excavations, piled foundations in challenging soil, and shoring/underpinning of adjacent buildings
• Unusual or long-span structural systems
• Major renovation projects involving significant structural modification of existing buildings
• Projects on sites with significant geotechnical complexity

Toronto's peer review requirement is communicated through the permit application process. Owners and engineers of record should verify with Toronto Building whether peer review will be required before committing to design and permit timelines — peer review adds time and cost that must be budgeted at project inception.

Who Can Perform a Structural Peer Review?

Peer reviewers must be P.Eng.-licensed structural engineers in good standing with PEO, with expertise in the structural system and building type under review. The reviewer must be fully independent — not employed by the same firm as the engineer of record, without a financial interest in the project, and without a prior relationship with the project team that would compromise objectivity.

For complex projects, the peer reviewer's credentials and experience should match the project type:

• Post-tensioned concrete high-rise: a peer reviewer with demonstrable high-rise PT concrete experience
• Deep excavation shoring and underpinning: a geotechnical-structural reviewer with specific excavation support experience
• Long-span steel roof: a reviewer with long-span steel and connection design experience

The CBO or commissioning authority sometimes specifies a list of acceptable peer reviewers or requires advance approval of the proposed reviewer's credentials before the review begins.

What the Reviewer Checks

A structural peer review covers the full scope of the structural design package:

• Design basis document / structural criteria: Are all applicable codes correctly identified? Are the load combinations, environmental loads (snow, wind, seismic), material properties, and performance criteria appropriate for the building type, location, and importance category?
• Structural system selection: Is the chosen structural system — steel frame, concrete flat plate, hybrid — appropriate for the span lengths, building height, lateral loads, and site conditions? Are the gravity and lateral systems compatible and adequately integrated?
• Structural calculations: Spot-checks of representative member designs (beams, columns, slabs, shear walls, connections, foundations) to verify that the engineer of record's calculations correctly apply OBC/NBCC load requirements and CSA design standard provisions.
• Foundation design: Comparison of structural foundation loads against the geotechnical engineer's recommended bearing capacities and pile capacities; pile cap designs; settlement analysis for adjacent structures.
• Connection designs: Review of critical connections — transfer beams, moment connections, column splices, collector elements — where design errors would have significant structural consequences.
• Construction drawing completeness: Sufficient detail for the contractor to build what the engineer designed — member sizing, reinforcement placement, connection hardware, weld sizes, and installation notes clearly shown.

The Peer Review Process Step by Step

1. Engage reviewer early: Identify and retain the peer reviewer before design is complete, so the review can be scheduled without delaying permit submission
2. Submit design package: Provide the complete structural drawings (100% permit-stage), structural calculations (all members and connections), geotechnical report, and design basis document
3. Round 1 review: Reviewer reads and checks the design; produces a written list of comments, questions, and required revisions — typically within 3–5 weeks for a mid-rise building
4. Engineer of record responds: The design engineer responds in writing to each comment — revising the design where required, or providing technical justification where the original approach is maintained
5. Round 2 review: Reviewer evaluates the response; issues a final peer review report confirming that outstanding issues have been resolved (or flagging unresolved items)
6. Report to CBO/authority: The peer review report is submitted to the building department or commissioning authority as a permit issuance condition

Managing the Peer Review Efficiently

Structural peer reviews run most efficiently when the engineer of record:

• Provides a complete, well-organized design package at submission — incomplete packages generate avoidable Round 1 comments requesting missing information
• Prepares a structured design basis document summarizing applicable codes, load assumptions, material properties, and design philosophy — this allows the reviewer to quickly confirm the design basis rather than reverse-engineering it from drawings
• Responds thoroughly and promptly to Round 1 comments — a complete, point-by-point written response that addresses every comment directly (with revised drawing or calculation reference for each revision) minimizes Round 2 back-and-forth
• Maintains an open technical dialogue with the reviewer — many peer review findings are genuine design improvements, not just bureaucratic hurdles; treating the peer reviewer as a professional peer rather than an adversary leads to better outcomes