Acceleration, directed and constructive

Acceleration claims arise when a contractor spends money to finish faster than it otherwise would. Sometimes the owner asks for it. Sometimes the owner refuses a valid extension and insists on the original date, which can force the contractor to accelerate without any instruction. This lesson covers both, the difference from ordinary mitigation, and the owner decisions that create or avoid the claim.

Learning outcomes

• Distinguish directed acceleration, constructive acceleration and mitigation.
• List the elements of a constructive acceleration claim in Canada.
• Explain how slow decisions on extension requests create acceleration claims.
• Value an acceleration claim from overtime and resource records.

The lesson

Directed acceleration

Directed acceleration is simple: the owner instructs the contractor to finish earlier than the contract requires, or to recover delay the owner is responsible for. It should be handled as a change, priced and recorded by Change Order or Change Directive (see Construction Phase lesson 16).

Constructive acceleration

Constructive acceleration happens without an explicit instruction. A Canadian law firm summary describes the elements as: an excusable delay; the owner refusing to recognize it and insisting on the original completion date, where an extension would have been reasonable; the contractor being forced to speed up as a result; and the contractor incurring additional cost [2]. Canadian decisions discussed in this area include W.A. Stevenson Construction (Western) Ltd. v. Metro Canada Ltd., used as an example of constructive acceleration, and Morrison-Knudsen v. B.C. Hydro on the meaning of acceleration [2].

Mitigation is not acceleration

Contractors have a duty to mitigate: reasonable steps, such as resequencing, to limit the effect of a delay. CCDC 2-2020 GC 6.6 includes a duty to mitigate for claims [1]. Mitigation is part of the contract price; acceleration, spending extra money to beat a date the contractor was entitled to move, is not. Where one ends and the other begins is often the argument [3].

The owner's trap

Most constructive acceleration claims start with an owner who does not decide. A valid extension request sits for weeks, someone says "hold the date", and the contractor works overtime. The fix is procedural: decide extension requests within a set time, in writing, and if the owner wants the original date held, say so as a priced instruction.

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.

Event E-04: the local utility connected permanent power 14 days late. Halvorsen gave delay notice on October 8, 2027 and requested 14 days. The extension was not decided. On October 15, the owner's project manager emailed Halvorsen: "Please hold the January 14 date." Halvorsen put interior trades on overtime from October 18 to November 12, when the owner finally granted the 14 days (Figure 2).

Halvorsen claimed $118,810 of overtime premium. The elements were mostly there: an excusable delay, a reasonable request, an insistence on the original date. But Halvorsen's GC 6.6 notice of intent to claim the cost arrived on November 15. Under the Supplementary Conditions' 10 Working Day limit, only the overtime from November 1 was covered. The owner's representative valued that period at $24,100 from Halvorsen's payroll records, and that figure carried into the settlement. The email cost the owner $24,100; deciding the request on October 9 would have cost nothing.

Your move

If you are the owner

• Decide extension requests within a set number of days. Put the deadline in the SCs.
• Never say "hold the date" informally. If you want acceleration, instruct it and price it.
• Separate mitigation from acceleration. Ask what the contractor would have done anyway.
• Audit overtime records. Premium only, on the affected work, in the affected period.

If you are the contractor

• Request the extension in writing, with a TIA. A reasonable request is element one.
• Get the refusal or insistence in writing. It is element two.
• Give GC 6.6 notice before you spend. Late notice cut Halvorsen's claim by 80%.
• Track acceleration costs separately. Overtime premium, extra shifts, extra equipment.

Common mistakes

1. Owners leaving requests undecided. Silence plus pressure creates the claim.
2. Claiming mitigation as acceleration. Reasonable resequencing is part of the job.
3. Late cost notice. Entitlement can fail even where the facts are strong.
4. Claiming full overtime cost. Only the premium over normal cost is extra.
5. Accelerating without proof of the refusal. An email or minute is essential.

Quick quiz

1. What distinguishes constructive from directed acceleration?

   1. Constructive is always cheaper
   2. Constructive happens without an explicit instruction, usually through refusal of a valid extension
   3. Directed is never paid
   4. They are the same

2. Which is not an element of constructive acceleration?

   1. An excusable delay
   2. Owner insisting on the original date
   3. Contractor incurring extra cost
   4. A signed Change Order

3. Is mitigation compensable as acceleration?

   1. Always
   2. No; reasonable mitigation is part of the contract
   3. Only for owners
   4. Only in winter

4. What limited Halvorsen's acceleration claim most?

   1. No delay
   2. Late GC 6.6 notice
   3. No overtime
   4. The weather

5. What should the owner have done on October 9, 2027?

   1. Nothing
   2. Decide the 14-day extension in writing
   3. Email "hold the date"
   4. Issue liquidated damages

Show answers and explanations

1. B. The owner's insistence on the original date does the work of an instruction.
2. D. If there is a Change Order, the acceleration was directed and priced.
3. B. Mitigation is a duty; acceleration goes beyond it.
4. B. Only overtime from November 1 fell within the notice window.
5. B. A prompt decision removes the basis for constructive acceleration.

Key terms

Directed acceleration

Acceleration the owner instructs, handled as a change.

Constructive acceleration

Acceleration forced by the owner's refusal of a valid extension and insistence on the original date.

Mitigation

Reasonable steps to limit the effect of a delay, part of the contract obligations.

Overtime premium

The extra cost of overtime above normal labour cost.

Extension request

A contractor's written request for more Contract Time, ideally with a TIA.

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. Wasel & Wasel, Actual acceleration and constructive acceleration in Canadian construction claims (July 31, 2023).
3. FTI Consulting, Mitigation and acceleration: what's the difference and why does it matter? (undated).
4. BRC, Northgate fact sheet (fictional case study, v1, November 4, 2026).

Verified on November 9, 2026.

Next lesson in this trackQuantum: extended site overhead