With a significant storm that has caused some major flooding (some urban areas in the five state area got more than six inches of rainfall), it is timely to advice our clients and friends to properly inspect and correct any flood damaged homes and other structures.
Flowing floodwaters generally exert greater forces on surfaces and structures than still waters of similar depth. The three types of pressures caused by flooding are: hydrostatic, hydrodynamic and debris impact (frictional forces).
Moving water flowing around a structure imparts lateral and vertical forces to the structure associated with the weight of the water (hydrostatic and buoyant forces), lateral impact forces associated with the momentum of the moving water (hydrodynamic forces), and frictional forces along the surfaces contacted by the moving water that can scour and erode adjacent soils and remove wall coverings and appurtenances.
Hydrostatic and hydrodynamic forces can damage elements of a building structure and erosion and scour caused by the frictional forces can weaken the structure by removing supporting soil and undermining the building foundation. Differential floodwater levels acting against the walls of the building, either from the exterior during the initial flooding of the property or trapped within the interior of the building when the exterior floodwaters recede, exert hydrostatic pressures upon the building.
Damages usually associated with flood damage to homes and other structures include, but are not limited to:
· Saturation of soils causing footings, piers, and foundations to become unstable or fail,
· floatation may cause support and anchoring systems to become unstable or fail,
· lateral displacement of the homes ceilings, walls and floors,
· cracking of wall and ceiling finishes,
· saturation of insulation materials in floors and walls,
· saturation of floor framing and decking materials,
· siding, wall sheathing and interior wall finishes,
· mechanical duct work located in the crawl space of the homes,
· gas and oil lines and connections in and under the home,
· plumbing systems of the home (drain/waste/vent and water),
· electrical systems of the home in floors and walls,
· furnace and water heater,
· mold from water damage or sustained high humidity levels.
During the property structural damage assessment, it is important to properly inspect the risk for signs of scuff marks, abrasions, or other evidence on or around the building that may indicate impact or recent shifting or movement of the building framing or foundation consistent with the application of hydrodynamic forces or hydrostatic forces from floodwaters. It is also important to observe any erosion or scour of soils around the perimeter of the building that could be consistent with detrimental velocity flow.
Metropolitan Engineering, Consulting & Forensics (MECF)
Providing Competent, Expert and Objective Investigative Engineering and Consulting Services
P.O. Box 520
Tenafly, NJ 07670-0520
Tel.: (973) 897-8162
Fax: (973) 810-0440
E-mail: metroforensics@gmail.com
Web pages: https://sites.google.com/site/metropolitanenvironmental/
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