Forensic Engineering is the investigation of materials, products, structures, or components that fail or do not function as intended. This field encompasses various engineering disciplines to determine the cause of an event.

For example:

• A mechanical engineer might assess a gear in a cordless drill that strips under normal use, leading to numerous product returns.
• An electrical engineer could be tasked with identifying the source of an outage in a city's electrical grid.
• A civil engineer might investigate the failure of a dam embankment.
• A structural engineer could examine the collapse of a masonry wall.

In my experience, forensic engineering is not a distinct field separate from these core disciplines. Instead, it uses the scientific method combined with design knowledge and practical experience to determine what happened, why it happened, and sometimes, how to repair or modify the affected elements.

Over the past 15 years, I have conducted more than 1,000 forensic studies, primarily for insurance companies to assess losses or claims. My field studies began with flood damage from Hurricane Sandy in New Jersey. They expanded to include structural damage from fires, vehicle impacts, tornadoes, hail, tree falls, deficient construction, explosions and many other causative events.

Insurance companies, realtors, and homeowners often request this service to determine the cause of cracks, deflection, or failures in foundation walls. One notable example recently involved a homeowner concerned about cracks in an exterior brick wall.

During the site assessment, I found cracks around a window in the south wall of a one-story addition on the west side of the original dwelling. The interior floor also deflected or sagged, and the drywall around the window had cracked.

The addition had been built over a crawlspace that had concrete block foundation walls. As I entered the crawlspace, I discovered that the cracks and sagging floor were due to the partial collapse of the south foundation wall, under the window. The other sections of the foundation were generally in good condition.

While identifying the cause of the reported issue could have concluded the assessment, one question remained. What caused the partial collapse of that section of the foundation, which then caused the cracks? I didn’t want to stop until I figured it out.

Using the scientific method, I hypothesized that there was something different about that section of the foundation, compared to the other walls. Further observation and analysis revealed that the concrete block of the addition contained iron foundry slag. The stone aggregate used everywhere else had been replaced in this section, most likely to reduce production costs.

So, I could now pinpoint the issue and cause. The slag section was not as durable. Once exposed to moisture, the remnant iron inside the slag had oxidized and expanded. This weakened the block until it crumbled.

Looking again at ground level, the south wall of the home had a flower bed under the window, and so that area had been exposed to elevated moisture. In the other parts of the home, the foundation walls were protected from moisture by the garage, a concrete patio and the main dwelling.

Although this example may seem mundane compared to catastrophic failures seen in the news, the south foundation wall, with its flower bed and oxidized slag block, illustrates the forensic engineering process well. Simply described, it is the combination of the scientific method with the knowledge and experience of a practicing engineer.

And the lesson I’m learning with each example is, wherever possible, don’t cut corners with sub-par materials.