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But-For Construction Delay Analysis – The Collapsed As-Built Method by Andrew Sargent

But-For Construction Delay Analysis – The Collapsed As-Built Method

January 13, 2021

As discussed in previous posts on the topic, there are several methods by which time impacts to a project can be analyzed, including windows analysis, time impact analysis, as-planned versus as-built, and impacted as-planned. This post focuses on one of the more commonly used methodologies: the collapsed as-built, or but-for schedule analysis. Here we will:

  • Provide an overview of the collapsed as-built method
  • Discuss its use in construction delay claims
  • Examine the strengths and drawbacks of the method from the perspective of construction claims analysts 

Fundamentals of the Collapsed As-Built Method

The key principle of the collapsed as-built schedule analysis method is the demonstration of a project’s completion without the effect of delays caused by another party. The philosophy is that without the other party’s delays, the project would have been completed earlier and thus the claimant is entitled to a time extension for the difference between that earlier date and the actual completion.

A collapsed as-built schedule analysis — also known as the but-for analysis — starts with developing or refining the project’s as-built schedule. Next, actual delay events caused by two parties – typically the contractor and the owner are identified. The delays attributable to one of the parties are removed from the as-built schedule, thereby “collapsing” the schedule and leaving the delays caused solely by the other party clearly visible. The resulting collapsed as-built schedule illustrates how the project would have progressed “but-for” the delays of the other party.

The collapsed as-built method is effectively the inverse of the impacted as-planned method. In the impacted as-planned method, the analyst estimates project delays by taking an as-planned schedule and adding in known delay impacts. The impacted schedule is compared with the as- planned schedule to quantify project delays.

In the Collapsed As-Built method, the reverse is performed. The analyst takes the as-built schedule and subtracts known delay events to create an “unimpacted” schedule. This unimpacted schedule is compared with the as-built schedule to quantify project delays.

When to Apply the Collapsed As-Built Method

The use of the various schedule analysis methods depends on different factors, including:

  • The type and complexity of the project
  • Time constraints
  • Availability of project documentation

Certain characteristics unique to the dispute will determine whether the collapsed as-built may be appropriate for the situation.

Ultimately, but-for schedule analysis is most effective in situations where contemporaneous updates or a baseline schedule does not exist. Other schedule analysis models rely heavily on this data so when it is not available the collapsed as-built approach provides a path forward.

Strengths of the Collapsed As-Built Method

The fundamental concept of the collapsed as-built schedule analysis or but-for schedule analysis that the effect of a party’s influence can be measured by removing that influence and comparing the results – is easy for most audiences to grasp. As such, the approach provides a level of comfortability that draws many to use the method. In turn, the results of a collapsed as-built delay analysis are often easy to understand and present. Below are some other advantages to the model.

A straightforward way to measure the impact of concurrent delays

One area of delay analysis that convolutes most construction delays claims is that of concurrent delay. Evaluating concurrent delay impacts can be one of the more difficult aspects of any analysis. The collapsed as-built method offers a straightforward approach to evaluating concurrency and is easy to convey to the opposing side. The reason is that evaluation of concurrent delays caused by the other party is inherent in the method itself. Identifying the actual delays of both parties is a required step in the analysis whenever appropriate. The collapsed as-built schedule that results from the analysis, in theory, depicts the delay caused by the claimant’s own issues. 

Fewer resources are needed to complete the analysis

Performing a collapsed as-built analysis generally requires less time and effort when completed to other forensic delay analysis methodologies such as a windows analysis. As such, use of the collapsed as-built method may be appropriate in situations where the time to complete the analysis, or the budget associated, is limited.

Weaknesses of the Collapsed As-Built Method

A major drawback to the as-built schedule analysis model is that the absence of contemporaneous schedule data can make it more susceptible to manipulation. This is because such information is critical to the reliable development of the as-built schedule that forms the very basis of the analysis.

Because aspects of the as-built schedule that forms the basis of the analysis often relies on subjectivity, an analyst can frame the analysis as needed to illustrate their argument. The root issue is the data used to develop the as-built schedule. It is inevitable that the opposing side will challenge the as-built start and finish dates for activities, making contemporaneous documentation critical to establishing the utilized dates.  

Furthermore, based on the identified actual dates, as-built schedule logic is applied between the activities. The determination of the appropriate logic can be highly subjective and have a drastic influence on the findings of the analysis. Establishing the validity of the as-built schedule data is paramount to any delay analysis that relies on the collapsed as-built method. This can be a difficult task if contemporaneous project record information is not available or limited. 

Summary of the Collapsed As-Built Method

The collapsed as-built method is recognized as an adequate method to determine delay allocation. But-for analysis of delays provides a simple and easy to understand solution to quantifying project impacts. This analysis is usually done — and works best — with projects that have good as-built schedule information but lack contemporaneous schedule information, such as monthly updates, or there is no reliable baseline schedule available. The lack of contemporaneous information, however, also lends itself to criticism of the as-built schedule developed by the claimant. Therefore, it is important to maintain strict guidelines and thoroughly consider all available project documentation.

If you have questions about this brief discussion on the Collapsed As-Built Method or other delay analysis models, or to learn more about VERTEX’s Construction Claims Consulting services, call 646.553.3500 or submit an inquiry.

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