Structural investigations of both historic and non-historic buildings are a specialty of our firm and may be conducted for reasons of pathology: to determine if anything is wrong with an existing structure. Or they may be of a more forensic nature. Whatever the reason, we use all available technologies, from visual observation to sophisticated non-destructive techniques. The end result is a comprehensive study of the particular building or element under study.
Our first task is to collect as much archival information about the building as possible – its original date of construction; original architect and engineer; availability of existing drawing, particularly framing plans, column schedules and details; information on floor systems and wall thicknesses. We interview all persons who might have knowledge of the building’s structural system, including maintenance staff, former contractors, former architects/engineers or anyone who has written about it.
We also conduct visual conditions surveys, without making any destructive probes. These consist of visual observations using high power optical instruments such as telescopes, binoculars, and telephoto lenses where applicable. We note any cracks, deflections, deformations, inclinations, damage, water stains, spalls, corrosion, rot, etc. Information is recorded on photographs, electronic images and drawings. From our experience, we are often able to predict what is occurring in the structural members that may be concealed behind architectural finishes.
We have pioneered in the use of non-destructive evaluation techniques (NDE) to assist in evaluating existing structural conditions. We have made extensive use of impulse radar and acoustic wave technology (impact echo and pulse velocity) in order to “see” into solid and dense material without actually disturbing it. Infrared thermography is a great aid in determining the presence of moisture in exterior walls and can also be used to locate hidden flues and chases. With a very minimal intrusion into structures that have hollow cavities, boroscopes (fiber optic devices) have proven very useful. Magnetic detection is very useful in locating ferrous metal products.
We are very sensitive to the requirements of a building owner and to the recommendations for historic buildings to disturb as little of the original fabric as possible. We can often glean a great deal of information from very few probes.
The final result is a comprehensive, well documented structural investigation report.