When you look at the picture above, it may be easy to tell what damage was caused by a vehicular collision to the front of a residential structure. What the picture doesn’t show is possible damage to the foundation or to the walls and door frames inside of the house. Cracks may be visible throughout the house, but how do you tell what was there before the accident? The trained eye of an engineer can discern what was caused by the vehicular event and what was pre-existing, a skill that takes years to develop. At Klepper, Hahn & Hyatt, we have structural engineers who have extensive experience in their field and use their knowledge when called upon to investigate virtually any form of damage to a residential or commercial property which could include anything from a vehicular accident to fire damage to a partial structural collapse as a result of snow and ice accumulation.

Vehicles hitting buildings in particular is quite prevalent. There is no single, comprehensive source of this type of data, but based on a study by the Storefront Safety Council (1), it is projected that there are at least 100 collisions between American drivers and building structures every day, or approximately 36,500 impacts per year, and that is probably the lower bound. They also estimate that these car-on-building accidents result in approximately 16,000 injuries and 2,500 deaths each year.

Our forensic engineers work with a variety of clients, including insurance companies and attorneys, to aid in the investigation of residential and commercial properties. The role of the engineer is to visit the site, gather evidence, analyze the information, and report their findings to the client. The work of a forensic engineer is impartial and the report reflects their direct observations.



To learn more about our forensic engineering services click here.

1.      https://slate.com/business/2022/06/car-crash-buildings-how-many.html

By Jim D'Aloisio P.E., LEED AP

Although many building designers consider collaboration to be a great asset, some designers silo themselves. Structural engineers sometimes limit their involvement to the primary structural elements – beams, columns, floor and roof deck, and such – and ignore the impact of the structure on the envelope performance. And some architects give the structural details a wide berth, even when they intersect the thermal building envelope. But building systems are always holistic. For example, exterior wall sheathing is critical to providing structural bracing of exterior studs, and it may serve as a component of the building’s lateral force-resisting system. It also frequently serves as a substrate for the air barrier and weather-resistant barrier, among other functions. Collaboration by the members of the design is critical to a successfully performing building. Here are some aspects of these “gray areas:"

• Steel gable roof truss overhangs. Regardless of whether the thermal envelope is at the sloping roof plane or the attic or ceiling level, these overhangs pass through the thermal plane unless they are either completely enclosed with an air barrier and insulation or radically altered to break the overhangs with thermal breaks. How often is this overlooked? See Figure 1.
• Other wall-to-roof conditions. We discussed this in detail in a previous Corner of the Envelope (linked here). Traditionally, commercial buildings feature a steel edge angle for attachment of perimeter wood blocking, which provides much, much more structural capacity than is necessary to support a roof drip edge. One option we have been exploring is to ditch the steel angles and provide a properly specified and detailed section of nailer base - OSB adhered to rigid insulation, screwed down to the steel roof deck. This is perfectly adequate structural support for the roof edge and does not interfere with the thermal envelope continuity. And it probably costs less to install!
• Bottom of wall conditions. Where the thermal wall envelope intersects the foundation insulation, architectural/structural coordination is critical. If the primary insulation is on the outside face of the superstructure wall, it may be best to insulate the exterior face of the foundation wall, rather than the interior, where there needs to be some type of workaround around the slab edge. Exterior foundation insulation can create better thermal continuity. If the building has exterior masonry, a low-conducting material such as Foamglas® can be used to prevent a thermal bridge at the foundation wall.

To find more examples of "gray areas" click here.

We believe that paying attention to these “gray areas” results in a better coordinated and better performing building overall. Let’s break down the silos and collaborate!

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