What Happens in a Forensic Engineering Investigation? From Site Inspection to Report of Findings

A forensic engineering investigation answers two questions about a failure or a loss: what caused it, and when it happened.

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Any investigation follows this sequence: define the question, gather documents, inspect and document the site, test when warranted, analyze the evidence against applicable requirements, and put the results in a Report of Findings that can withstand scrutiny.

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Attorneys who know what happens at each stage tend to get more out of the engineer (and so do their cases). See below for a full rundown of what that sequence looks like in practice, and get a broader picture of the role by reading our article on what a forensic structural engineer does.

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What questions are a forensic engineer asked to answer?

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Every investigation starts by defining the questions that need answers. Sometimes the questions are narrow: Did this roof covering fail from wind, or from something else? Sometimes the questions are broader: Why did this structure perform the way it did, and when did the underlying condition begin?

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The question shapes everything that follows, including which documents are relevant, what the site inspection needs to capture, and whether any testing is needed. It also sets the boundary of the engineering opinion. A forensic engineer evaluates physical cause and timing. Whether a given cause falls within a policy, contract, or standard of care is a question for counsel.

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What happens before the site visit?

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More forensic engineering work happens at a desk than people might realize. Depending on the matter, the engineer may ask for:

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• Plans, specifications, and shop drawings
• Permits and inspection records
• Photographs and video, especially anything taken before repairs
• Maintenance, repair, and prior-claim records
• Manufacturer documentation for the products involved
• For storm matters, the dates of the events in question

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The engineer also pulls independent sources where they apply, including historical weather data for the property’s location, the code edition in force when the structure was built or altered, and the manufacturer’s installation requirements for the products involved.

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This review does two things. First, it provides the engineer with a guide for what to look for on site. Second, it builds out the documentary half of the timeline. Physical evidence shows what a condition looks like now, but documents show what it looked like earlier.

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What happens during the site inspection?

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The site inspection is where the physical record is developed. In general terms, the engineer:

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• Observes and documents the as-found condition before anything is disturbed, with photographs, measurements, and notes
• Looks at the whole system, not only the point of failure, because the cause of a problem is often some distance from where it shows up
• Measures and samples where the question requires it, including the dimensions of a damaged component, the slope of a walking surface, or the thickness of a corroded section
• Opens up selected areas when the relevant detail is concealed, which may mean removing a section of roofing, finish, or cladding to see the assembly behind it

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Where an inspection may alter evidence, the usual practice is to notify the other parties beforehand so that they can attend or object, and to document each step so the condition before and after is on record. Anything removed from the site is labeled, photographed, and tracked so its chain of custody is clear.

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Those steps protect the evidence, and they protect the opinion that will later rest on it. We’ve written about how much can be lost when an engineer comes in late in our article on when to bring a forensic engineer into a case.

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When is testing involved?

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Not every matter needs it. When it does, testing answers a specific question that observation alone can’t settle. Depending on the case, that may include:

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• Laboratory analysis of a material sample, such as a metal, a coating, or a roofing product
• Measurement of a site condition against a published method, such as the slip resistance of a walking surface or the light levels in an area
• Review of a product’s test reports against the conditions it was exposed to

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The result is one more piece of evidence, weighed alongside the site observations and the documents. Testing should never be used as a substitute for other portions of the investigation. Instead, it simply narrows the possibilities the rest of the evidence has already established.

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How does the analysis work?

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With the evidence in hand, the engineer compares what was observed against what applied across the governing code edition, the design documents, the manufacturer’s requirements, and the recognized standards for the component in question. The analysis looks for the explanation that fits all of the evidence, and it rules out the alternatives that don’t fit.

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That comparison yields two things. The first is causation: the physical mechanism that produced the condition. The second is duration: when that condition likely began, which the documents, the weather record, and the physical indicators help establish. Causation and duration are usually the two questions that make or break a case, and they’re analyzed together. The same approach applies whether the subject is a possible construction defect, a storm claim, a premises condition, or a storage tank.

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What is a Report of Findings?

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The Report of Findings is the written product of the investigation. It documents what was asked, what was reviewed, what was observed, how it was analyzed, and the engineer’s conclusions, along with the photographs, measurements, and sources that support each step. In general, a report covers:

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• The scope, including the questions the engineer was asked to answer
• The documents and data reviewed
• The site observations, with photographs and measurements
• Any testing performed and its results
• The analysis: how the evidence was evaluated and against what requirements
• The findings, stated to the degree the evidence supports them
• The limitations: what couldn’t be observed, and what the findings depend on

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A report written this way can be followed by someone who wasn’t there. That matters because the people who will read it most closely are usually the ones with a reason to disagree with it. Each conclusion traces back to a specific observation, document, or measurement, so a reader can check the reasoning rather than take it on trust.

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What happens after the report?

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The report may be the end of the engineer’s role or the start of a longer one. In some matters, it supports a resolution without testimony. In others, the engineer is deposed, responds to another expert’s analysis, or testifies. New information, like documents produced later or a change in the physical condition, may require a supplemental report.

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The basis for the opinion stays constant. Testimony explains the report and the evidence behind it, which is why the investigation is built the way it is, so the report can carry that weight. Whether an engineer’s work is discoverable and how an expert is designated are matters counsel handles.

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What can attorneys do to help an investigation go well?

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A few things make a measurable difference:

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• Preserve the condition: Hold off on repairs and cleanup until the site has been documented, or document it yourself before they start.
• Collect the documents early: Plans, permits, photographs, and maintenance records are easiest to find while the people who have them are still involved.
• Share the question: The engineer needs the dispute’s actual issues to scope the work. The analysis is more useful when it answers the question that will be asked.
• Give notice: Where an inspection may alter evidence, notifying the other parties beforehand protects the result.

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Have a matter where the cause, or the timing, is in dispute?

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WindForce investigates structural failures, storm claims, construction defects, premises conditions, and storage tank failures for attorneys, carriers, owners, and contractors. We’re happy to talk through what an investigation would involve in your case.

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Request a case consultation.

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Frequently Asked Questions

What is a Report of Findings?

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It’s the written product of a forensic engineering investigation. It documents the scope, the documents reviewed, the site observations, any testing, the analysis, the engineer’s findings, and the limitations on them, with the photographs and sources that support each step.

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Can a forensic engineer investigate a property that has already been repaired?

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Often, yes, though with less to work from. The engineer relies more on pre-repair photographs, the repair contractor’s records, any removed materials (if kept), and the documentary record. The findings are stated to the degree that the evidence supports them, which is why documenting a condition before repairs matters.