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Concurrent Delays in Construction

What Are Concurrent Delays in Construction?

Concurrent delays happen when two or more delays overlap and affect a construction project. These delays can come from the contractor, the owner, or even outside events like bad weather.

Types of Delays

Owner-Caused Delays

  • Late approvals.
  • Delayed access to the site. Typically permits. 

Contractor-Caused Delays

  • Poor planning. 
  • Not enough workers or equipment.

External Delays

  • Bad weather.
  • Labor strikes.

Example of a Concurrent Delay

Imagine a project to build in an office building in Ontario, 

  • Owner Delay- The owner is two weeks late approving building permits.
  • Contractor Delay- The contractor isn’t ready to mobilize on site due to subcontractor contract issues, causing a three-week delay.
  • External Delay- A winter storm shuts down work for one week.

How to Spot Concurrent Delays

Overlap in Timing

Delays must happen at the same time.

Critical Path Impact

Both delays need to affect either the critical path (based on negative float) or the longest path (determined by project duration). According to the Longest Path Theory, delays on the longest path always impact the completion date, whereas the Critical Path Theory focuses on activities with negative float. A delay is considered concurrent if it impacts the project completion date by affecting either the critical or the longest path and occurs simultaneously with another delay. A delay is only considered concurrent if it affects the longest path and has the same impact on the project’s completion date as another delay.

Independent Causes

Delays need different reasons. For example, one delay could be from the owner, another from the contractor.

Project Completion Impact

Both delays must push back the final completion date.

Theory of Criticality and Longest Path Theory

There is a distinction between activities that are critical (with negative float) and those on the longest path. A critical activity might not be on the longest path, meaning its delay doesn’t necessarily affect the project completion date.

Key Points:

  • Delays on the longest path always impact the end date.
  • If a critical activity (not on the longest path) and a longest path delay occur simultaneously, the latter determines the project completion date.
  • This concept aligns with the Longest Path Theory, contrasting with the Theory of Criticality, which focuses on negative float for defining concurrent delays.
  • According to the Longest Path Theory, only delays on the longest path directly influence the schedule completion date. Concurrent delays arise only when multiple activities equally impact the end date.
  • A critical delay outside the longest path cannot offset or mitigate a longest path delay.
  • This debate is not settled law or standard practice but is a key consideration in discussions about concurrent delay in project controls.

How to Handle Concurrent Delays

Understand the Delays

Know if they’re caused by the owner, contractor, or external events.

Check the Contract

  • Does it allow for extensions of time (EOT)?
  • Does it explain cost reimbursement rules?
  • Are there clauses on how to deal with overlapping delays?

Notify Everyone

Send written notices about delays. Include:

  • What caused the delay.
  • How it’s affecting the schedule.

Analyze the Delays

Use scheduling tools to figure out what’s causing delays:

  • Critical Path Analysis- Find the tasks delaying the project.
  • Time Impact Analysis- Add the delays to the schedule and see the effect.

Split Responsibility

  • Owner-Caused Delays- The contractor might get more time and costs reimbursed.
  • Contractor-Caused Delays- No time extension or reimbursement.
  • External Delays- The contractor might get more time but usually no reimbursement.

Legal Context in Canada- CCDC 2 Example

Excerpt from CCDC 2 – 2020, used for educational purposes. Copyright Canadian Construction Documents Committee.

  • Owner Delays- Contractors get extra time and may be reimbursed for costs.
  • External Delays- Contractors get more time but no reimbursement unless linked to the owner.
  • Contractor Delays- No extra time or cost reimbursement.

Quick Recap

  • Concurrent delays overlap and affect the project’s finish date.
  • Use your contract to figure out what’s fair.
  • Analyze the delays to split responsibility fairly.
  • Communicate and document everything to avoid disputes.

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