Third-Party Structural Review in Ontario

A third-party structural review in Ontario is an independent technical assessment of structural design documents prepared by another engineer. The purpose is to verify compliance with the Ontario Building Code (OBC – current edition), referenced CSA standards, and accepted engineering practice.

This process is commonly required for complex, high-risk, or unconventional structures. Municipal building officials, project owners, insurers, or peer engineers may request it.

Regulatory Framework in Ontario

Structural design in Ontario must comply with:

• Ontario Building Code (O. Reg. 332/12, as amended)

• OBC Division B, Part 4 – Structural Design

• CSA A23.3 – Design of Concrete Structures

• CSA S16 – Design of Steel Structures

• CSA O86 – Engineering Design in Wood

• NBC-referenced load standards (e.g., snow, wind, seismic)

A third-party structural engineering review evaluates whether the submitted design aligns with these requirements and whether assumptions are technically justified.

When Is a Third-Party Structural Review Required?

A third-party structural review in Ontario may be required for:

• Tall buildings or large assembly structures

• Transfer systems or long-span framing

• Deep foundations or unusual soil conditions

• Seismic force-resisting systems

• Structural alterations to existing buildings

• Projects involving alternative solutions under OBC Division C

Municipalities may request independent review where structural complexity exceeds routine building department evaluation capacity.

Scope of a Third-Party Structural Review

The review focuses on structural adequacy and code compliance, not redesign. Typical scope includes:

• Verification of design loads (snow, wind, seismic)

• Review of load paths and structural continuity

• Assessment of member sizing and detailing

• Foundation design consistency with geotechnical data

• Conformance with referenced CSA standards

• Review of general notes and specifications

Calculations are independently checked for methodology and governing limit states (ULS and SLS, where applicable).

Key Elements Reviewed

Component	Verification Focus	Code Reference
Gravity Loads	Dead, live, snow loads	OBC Div. B, Part 4
Lateral Loads	Wind & seismic forces	OBC Div. B, 4.1.7 & 4.1.8
Concrete Design	Strength & detailing	CSA A23.3
Steel Design	Member resistance & connections	CSA S16
Wood Design	Bending, shear, connections	CSA O86

The reviewer confirms that the structural system provides a continuous and reliable load path from roof to foundation.

Review Deliverables

A typical third-party structural review in Ontario results in:

• Written technical review letter

• Marked-up drawings (if required)

• Summary of deficiencies or clarifications

• Statement of compliance or conditional acceptance

Where required, the reviewing Professional Engineer (P.Eng.) seals the review documentation in accordance with Professional Engineers Ontario (PEO) practice standards.

Responsibilities and Professional Practice

The original design engineer remains responsible for the structural design.

The third-party reviewer:

• Provides independent technical verification

• Identifies non-compliance or coordination gaps

• Recommends corrective actions

The review does not transfer design liability unless contractually specified.

Benefits of Independent Structural Review

• Reduces structural risk

• Enhances code compliance confidence

• Improves coordination between disciplines

• Supports municipal approval process

• Provides technical validation for complex systems

For high-risk structures, an independent structural review strengthens project defensibility and documentation integrity.

Conclusion

A properly executed third-party structural review in Ontario ensures structural systems comply with the Ontario Building Code and referenced CSA standards. It strengthens quality control and reduces technical and regulatory risk in complex construction projects.

At Parsways Inc., we provide independent third-party structural reviews in Ontario aligned with OBC requirements and CSA standards. Our reviews are calculation-based, code-referenced, and delivered with clear technical documentation suitable for municipal submission and professional coordination.

---

FAQs

1. Does a third-party structural review replace the original engineer?

No. The original engineer retains design responsibility.

2. Is a third-party review required by the Ontario Building Code?

Not universally; municipalities may require it for complex or alternative designs.

3. Can a third-party reviewer redesign deficient elements?

Not within a review scope; redesign must be issued by the design engineer.