Construction Schedule Delay Claims: A Plain-English Primer

What Is a Construction Schedule Delay Claim?

A construction schedule delay claim is a formal request by a contractor (or owner) for additional time or money due to events that push the project completion date beyond the contractual milestone. These claims are common in complex projects where multiple trades, suppliers, and stakeholders interact. To succeed, the claimant must prove that a specific event caused a measurable delay and that the contract or law entitles them to relief.

Delay claims typically fall into two categories: time-only claims (seeking an extension of the contract completion date without additional compensation) and time-and-money claims (seeking both a time extension and recovery of associated costs such as extended overhead, labour inefficiency, or acceleration expenses).

Why the Schedule Is the Key Evidence

The project schedule—usually a CPM (Critical Path Method) schedule in Primavera P6—is the backbone of any delay claim. It shows the planned sequence of activities, dependencies, and the critical path. When a delay occurs, the schedule can demonstrate:

• Which activities were affected and by how many days.
• Whether the delay impacted the critical path (and thus the project completion date) or only non-critical work.
• The causal link between the delaying event and the schedule slippage.

Without a properly maintained, updated schedule, a delay claim becomes a credibility battle. Courts and boards often view schedules as the best evidence of what actually happened, provided they are realistic, logically tied, and updated regularly.

Common Methods for Analysing Delays

Several forensic schedule analysis techniques are recognised in the construction industry. The choice depends on the contract, the available data, and the complexity of the delay.

As-Planned vs As-Built (Simple Comparison)

This method compares the original baseline schedule (as-planned) with the final as-built schedule. The difference in total float or completion date is attributed to all delays, without separating responsibility. It is easy to prepare but often too simplistic for disputed claims because it does not isolate the effect of individual events.

Impacted As-Planned

Here, the analyst adds the delaying events (as delay fragments) into the original baseline schedule to see how they push the completion date. This method assumes that the baseline was perfect and that the delays occurred exactly as modelled. It is often criticised for ignoring project changes and productivity losses.

Collapsed As-Built (But-For)

Starting from the as-built schedule, the analyst removes the effects of the claimed excusable delays to create a “but-for” schedule showing when the project would have finished without those delays. The difference between the actual completion and the but-for completion is the compensable delay. This method is widely accepted because it uses actual performance data.

Time Impact Analysis (TIA)

The most rigorous method, TIA inserts each delay event into a contemporaneous schedule update (the schedule that was in place when the delay occurred). The analyst measures the impact on the critical path and completion date at the time of the event. TIA requires frequent, accurate schedule updates but is the gold standard for forensic analysis.

Excusable vs Non-Excusable and Concurrent Delays

Understanding the legal classification of delays is essential for building a claim or defence.

Excusable delays are caused by events outside the contractor’s control (e.g., weather, owner-directed changes, force majeure). Most contracts allow a time extension for excusable delays. If the delay is also compensable (e.g., owner-caused), the contractor can recover costs.

Non-excusable delays are caused by the contractor’s own actions (e.g., poor productivity, subcontractor failure). The contractor gets no relief and may be liable for liquidated damages.

Concurrent delay occurs when two or more independent delay events happen at the same time, each of which would have delayed the project. For example, an owner-caused delay (e.g., late design) and a contractor-caused delay (e.g., labour shortage) overlap. The legal treatment varies by jurisdiction, but generally, if the contractor can show that the owner’s delay would have caused the same overall delay regardless of the contractor’s own issues, the contractor may still get a time extension (but not costs). Proving concurrency requires a detailed forensic analysis that isolates the effect of each delay path.

Preparing Schedule Evidence with a Forensic Comparison

To build a credible delay claim, you need to present a clear, logical narrative backed by schedule data. Here are practical steps:

1. Maintain a proper baseline schedule that is approved by the owner and reflects the true plan. Avoid unrealistic logic or missing activities.
2. Update the schedule regularly (monthly is standard). Record actual start/finish dates, progress percentages, and remaining durations. Keep a copy of each update.
3. Document all delay events with contemporaneous records: emails, meeting minutes, weather logs, change orders, and daily reports.
4. Perform a forensic schedule comparison between the baseline and each update (or between baseline and as-built). Identify where the critical path changed and what events caused the slippage.
5. Use a recognised method (e.g., TIA or collapsed as-built) and be prepared to explain your assumptions.

You can run these checks free in the browser with Project Assure, a tool that parses your Primavera P6 XER locally and performs DCMA 14-point checks, GAO & NASA checks, EVM/S-curve, and forensic baseline-vs-update comparison. Nothing is uploaded; your data stays on your machine.

Common Pitfalls in Delay Claims

• Failing to prove causation – showing that an event occurred is not enough; you must prove it directly caused a delay to the critical path.
• Using a flawed schedule – a baseline with missing logic, negative float, or unrealistic durations will be attacked by the opposing expert.
• Ignoring concurrent delays – if the owner can point to a contractor-caused delay that overlaps, your claim for costs may be reduced or denied.
• Poor documentation – without daily logs, photos, and correspondence, your schedule analysis may lack supporting evidence.

Conclusion

Construction schedule delay claims are complex but manageable with a disciplined approach to schedule management and forensic analysis. The key is to start early: maintain a realistic baseline, update it diligently, and document every event that affects the critical path. When a dispute arises, a well-prepared schedule analysis using a recognised method—backed by contemporaneous records—will give you the strongest chance of success. Tools like Project Assure can help you perform the necessary checks quickly and securely, so you can focus on building your case.