Starting Construction Before Structural Drawings Are Finalized: Risks and Limitations

Starting construction before structural drawings are finalized may appear efficient when schedules are tight. In Ontario, however, early work can create technical, permit, inspection, and liability issues that are difficult to correct later.

Structural drawings define the load path, member sizes, connection requirements, foundation design, lateral stability, and limitations needed for code-compliant work under the Ontario Building Code (OBC).

Final Structural Drawings and Permit Coordination

For most building work in Ontario, construction or demolition cannot proceed unless the chief building official has issued the required permit. The 2024 Ontario Building Code came into effect on January 1, 2025, and permit submissions are reviewed against the applicable code requirements.

Drawings used for permit review must be sufficiently complete for the scope being approved. This applies to projects in Toronto, Mississauga, Vaughan, Markham, Hamilton, Kitchener, London, Ottawa, and Barrie.

Starting structural work before the drawings are finalized can result in:

• Permit comments that change the design

• Work installed outside the approved scope

• Delays during municipal inspection

• Rework where framing or foundations conflict with final details

Design Changes That Affect Structural Safety

Early construction often proceeds based on preliminary layouts, verbal direction, or architectural intent. These are not substitutes for finalized structural drawings.

Small design changes can affect the structural system, including:

• Beam size or bearing length

• Column location or base plate detail

• Footing size and reinforcement

• Lintel and opening requirements

• Connection type and fastener spacing

A wall opening, mezzanine support, rooftop unit, underpinning sequence, or slab modification may seem minor on site. Structurally, it can change how loads are transferred through the building.

Inspection and General Review Limitations

Structural engineers cannot treat unfinished or unapproved drawings as final construction documents. Field review depends on a defined design, an approved permit scope, and visible work that can be compared with the drawings.

Professional Engineers Ontario has noted that engineers should not perform field review for work requiring a building permit when the permit has not been issued for that work.

If construction advances too far before drawings and permits are complete, concealed work may require selective removal, testing, or additional investigation.

Partial Permits and Fast-Tracked Construction

Fast-tracked projects sometimes use phased or partial permits. This can be appropriate when the municipality accepts a clearly defined scope, such as foundation work only.

A partial permit is not permission to build beyond the approved portion. Contractors and owners should confirm:

• The exact scope covered

• Which drawings are approved

• Which work must wait

• Required inspection stages

This is especially important for commercial and industrial projects in Ontario where tenant schedules, equipment delivery, or lease commitments create pressure to start early.

Construction Risks Before Drawings Are Finalized

The main risk is not only that work may be incorrect. The larger issue is that the project loses a clear basis for responsibility, inspection, and code compliance.

Risk area	Practical impact
Permit review	Municipality may require revised drawings or stop work
Structural design	Installed work may not match final load requirements
Inspection	Concealed work may need to be exposed
Cost and schedule	Rework can exceed the time saved by starting early

These risks increase when site decisions are made without stamped structural drawings, final coordination, or written direction from the design team.

Better Coordination Before Site Work Starts

Before starting structural work, the project team should confirm that the structural scope is ready. This usually means the drawings are finalized, sealed where required, coordinated with architectural and mechanical/electrical drawings, and aligned with the permit status.

Where schedule pressure exists, the safer approach is early coordination with the building department and the engineer. If a partial permit is possible, the approved scope should be narrow, documented, and followed on site.

Conclusion

Starting construction before structural drawings are finalized can create avoidable risk in Ontario projects. Preliminary information may help with planning, pricing, and scheduling, but it should not be treated as final construction direction for structural work.

At Parsways Inc., we provide structural drawing review, permit-support documentation, and construction-stage coordination for Ontario projects. Our approach is to clarify what can proceed, what must wait for final approval, and what limitations apply before structural work is built on site.