Concurrent delay in Canadian law

Concurrent delay is where claims get hard. When the owner and the contractor both delay the critical path over the same period, who pays? Different jurisdictions answer differently, and Canadian law is less settled than many assume. This lesson explains how Ontario courts have approached it, what the main approaches mean in dollars, and why the best answer is a clause agreed before the problem arises.

Learning outcomes

• Define concurrent delay and distinguish it from sequential delay.
• Explain what the Ontario Superior Court said in Schindler v. Walsh about timing.
• Compare the main approaches: time without money, apportionment and full recovery.
• Draft or review a concurrency clause.

The lesson

What counts as concurrent

Concurrent delay needs two independent causes of delay, one at the owner's risk and one at the contractor's, both affecting completion over the same period. Sequential delays, one after the other, are not concurrent; each is assessed on its own. The SCL Protocol describes concurrency as an owner risk event and a contractor risk event both affecting the critical path at the same time [2].

Schindler v. Walsh

In Schindler Elevator Corporation v. Walsh Construction Company of Canada, 2021 ONSC 283, the Ontario Superior Court rejected the argument that concurrent delays must be co-critical with identical start and finish dates. It accepted that concurrent delays are usually overlapping events that need not begin and end together, and that assessing them means breaking the delay into parts and assigning responsibility, typically with expert evidence [3]. A rigid timing test would make concurrency almost impossible to prove and would not divide losses fairly.

Three approaches

Commentators note that Canadian courts have generally apportioned concurrent delay damages according to the parties' contributions, sometimes splitting evenly where the contributions cannot be measured, and that the law remains unsettled [4]. Internationally, the approach widely associated with the SCL Protocol gives time but not money for the concurrent period. Because outcomes are uncertain, many owners write the answer into the contract.

Concurrency clauses

A concurrency clause states what happens when owner and contractor delays overlap: typically an extension of time, no extension of costs for the concurrent period, and no liquidated damages for it. It should define concurrency, require the analysis method, and say how partial overlaps are treated. Agreeing it at tender costs nothing; arguing it in arbitration costs a great deal.

Northgate worked example

Northgate Distribution Centre (fictional) is a 12,000 m² tilt-up warehouse in Vaughan, Ontario, built by Halvorsen Builders Ltd. (fictional) under CCDC 2-2020, with Ridgeline Architects Inc. (fictional) as Consultant. See the Northgate fact sheet. This course follows one delay claim from first notice to settlement. Ready-for-Takeover (M9) was due Friday, January 14, 2028 and was reached on Tuesday, March 14, 2028: 60 calendar days late. All events, dates and amounts are illustrative.

In window W2, two events drove the critical path. Halvorsen's roof deck arrived 15 days late from its supplier (E-02). For 10 of those days, the mezzanine redesign (E-03), which had used up its 25 days of float, was also critical (Figure 2). Each would have delayed completion on its own.

Northgate's Supplementary Conditions include a concurrency clause: time, no money, no liquidated damages for concurrent days. So Halvorsen gets 10 days of extension and no cost for them. Without the clause, the owner's lawyer advised that a court might apportion: at a 50/50 split, 5 days of site overhead at the audited $7,200 per day, or $36,000. The clause saved that argument.

Your move

If you are the owner

• Put a concurrency clause in the SCs. Define it and state the result for time, cost and LDs.
• Track your own critical events. You cannot argue concurrency if you cannot show the contractor's delay.
• Don't overreach. Calling a sequential delay concurrent damages credibility.
• Get expert evidence on large claims. Courts expect it.

If you are the contractor

• Read the concurrency clause before bidding. Price the risk it gives you.
• Separate your delays clearly. Show where owner delay continued after yours ended.
• Claim time for concurrent periods. It protects you from liquidated damages.
• Document the overlap precisely. Partial overlaps change the numbers.

Common mistakes

1. Requiring identical timing. Schindler rejected that test.
2. Calling sequential delays concurrent. They are assessed separately.
3. No clause. Leaves the answer to a court or arbitrator.
4. Ignoring float. An event only becomes concurrent once it is critical.
5. Paying twice. Owners who forget concurrency pay for days the contractor also caused.

Quick quiz

1. What did the court reject in Schindler v. Walsh?

   1. That concurrency exists
   2. That concurrent delays must start and end at the same time
   3. Expert evidence
   4. Critical path analysis

2. Which pair of events can be concurrent?

   1. Two contractor delays
   2. An owner delay and a contractor delay over the same period, both critical
   3. A delay and a change order
   4. Two sequential owner delays

3. How have Canadian courts generally treated concurrent delay damages, according to commentators?

   1. Always full recovery
   2. Apportionment by contribution, sometimes evenly
   3. Always zero
   4. Only by formula

4. What does a typical owner concurrency clause give for concurrent days?

   1. Money only
   2. Time, no money, no LDs
   3. Nothing
   4. Double LDs

5. Without Northgate's clause, a 50/50 split of 10 concurrent days at $7,200 per day would cost:

   1. $0
   2. $36,000
   3. $72,000
   4. $129,600

Show answers and explanations

1. B. The court adopted a practical, overlapping view.
2. B. One owner-risk and one contractor-risk event, overlapping on the critical path.
3. B. Apportionment is the general tendency; the law is unsettled.
4. B. Time but not cost, and no liquidated damages.
5. B. 5 days × $7,200 = $36,000.

Key terms

Concurrent delay

Owner-risk and contractor-risk delays affecting completion over the same period.

Sequential delay

Delays that occur one after another, each assessed separately.

Apportionment

Dividing responsibility for delay damages between parties by contribution.

Concurrency clause

A contract term stating the time, cost and LD result for concurrent delay.

Co-critical

Two paths that are both critical at the same time.

References

1. Canadian Construction Documents Committee, CCDC 2-2020 Stipulated Price Contract, GC 6.4 to 6.6 and Part 8. Clause content checked against a publicly posted tender copy; buy the form from CCDC.
2. Fenwick Elliott, The SCL Delay and Disruption Protocol: a second edition (November 2017), summarizing the Society of Construction Law Protocol, 2nd edition (February 2017).
3. Sahil Shoor and Tristan Neill, Gowling WLG, Ontario Superior Court endorses practical definition of concurrent delay (March 24, 2021), on Schindler Elevator Corporation v. Walsh Construction Company of Canada, 2021 ONSC 283.
4. Robin Davis, Borden Ladner Gervais LLP, Concurrent delay remains a thorny issue, On-Site Magazine (undated).
5. Miller Thomson LLP, Ontario Court underlines the evidence and analysis required to establish critical path delays (July 2021).
6. BRC, Northgate fact sheet (fictional case study, v1, November 4, 2026).

Verified on November 9, 2026.

Next lesson in this trackDisruption and the measured mile