Scenario: The owners of Jones’ Marine, a marina with a wharf structure on a tidal saltwater river, cater to the operators of ships, barges, and large yachts. There are both diesel and gasoline fuel pumps at the edge of the wharf. In addition, a large mobile crane for lifting the large vessels out of the water for maintenance is in service at the wharf. This crane is driven out to the edge of the wharf deck suspended over the water, subjecting this deck and the structure beneath it to very high loading. They purchased the property from its former owners about 10 years ago and are conscientious about maintenance and upkeep of their thriving facility. They decide it is time to have a survey performed of the condition of the precast reinforced concrete piles and pile caps beneath and supporting the concrete wharf platform/deck. They are alarmed at what is discovered by this survey: Significant spalling Read More
Scenario: A young couple is excited about buying their first home. They pick it out from a catalog of house plans from the developer of a new neighborhood in town. It will be a brand new construction starter type bungalow home on a slab-on-grade foundation. For a cost adder, which is considerable to them, they decide to upgrade the finished flooring from carpeting to hardwood laminate. Unfortunately, after only a few weeks of residency, the hardwood planks begin to buckle and separate from the slab throughout the house. They do not know what is causing it, or what to do to remedy it, Read More
Flashing is a hot-button topic amongst residential designers, builders, and claims adjusters alike. In fact, currently one of the most prominent construction defect claims that we see involves moisture intrusion around improperly flashed window openings in wood-framed structures. Other trouble spots include the roof penetrations at chimneys and vent pipes. Read More
The facts presented in this blog lead to an interesting story. During the heyday of the residential construction boom in coastal South Carolina circa 2005, many General Contractors were forced to go out-of-state to find framers and other subcontractors due to the demand creating a local labor shortage. It turned out that the state of Texas had excess capacity and availability of framers and carpenters. Many Texas framing crews came to South Carolina to satisfy the shortage. It soon became apparent that the Texas crews, many of which were from inland locations, were accustomed to installing 4’x8’ exterior wall sheathing with the long dimension vertical, i.e., parallel to the studs. It is especially important and required that the long dimension be oriented perpendicular to the studs. Laboratory testing has shown that Read More
Construction using concrete masonry blocks or units (CMU) is ubiquitous in the United States today, and in fact in the whole modern world. CMU blockwork is a very versatile and relatively economical building material. It is naturally strong in compression, but with reinforced, grout-filled cells, it can also withstand large shear, bending, and tensile loads imparted by lateral wind or seismic events. In this article, I will discuss the various types of CMU designs, as well as terminology, construction techniques, and application uses.
The design of CMU is typically comprised of hollow concrete “face shells” with Read More
Hurricane and Tropical Storm strength wind forces can wreak havoc on wood-framed residential structures. One of the primary hazards is the negative pressures which can develop on the exterior building envelope when the structure is subjected to the high encircling winds. These negative pressures act like the suction of a giant vacuum on a dwelling’s roof diaphragm, which produces enormous uplift forces throughout the entire structure. The leeward walls are also subjected to negative pressures, while the windward walls take the brunt of the positive wind pressures. The uplift on the roof is caused by what the author dubs “the airplane wing effect”. In other words, Read More
From corrosion to site drainage, coastal regions present a host of unique and challenging issues for homebuilders and residential property owners alike. In this article, issues specific to coastal residential foundation installation and in-service function will be addressed. “Coastal residential” will refer to single-family homes within AE or VE tidal flood zones for the purposes herein. These locations typically exist in areas with close proximity to saltmarsh or beachfront, or on barrier sea islands. Per FEMA, in AE zones, the elevation of the first finished floor must be above the flood elevation for the building site. In VE zones, the elevation of the lowest horizontal structural member must be above the flood elevation for the site. Most building jurisdictions also require a minimum of (1) foot of freeboard, or additional space, between the flood elevation and these building features. As a result of these requirements, coastal residential structures must be supported by either crawl-space or elevated “drive-under” style foundations. It should be noted that wall-type foundations are prohibited in VE zones, and structures within these zones are required to be supported by monolithic elements such as columns, piers, or piles. Slab-on-grade type foundations are not permitted in flood zones where the foundation will exist within the flood plain. Read More