Professional Engineering Inspections has been providing residential and commercial inspection and consulting services for existing and new construction in the Greater Houston area for over 28 years. Our services include prepurchase condition of property inspections, inspection of new construction, legal inspections, as well as inspections and consulting services where our clients may have specific needs. Our experience in construction consulting, where we are often asked to help find and solve construction related problems, is reflected in our inspection work and the quality of our resulting inspection reports. Our quality inspection services and reporting provide our clients with information that is useful in making an informed decision through narrative format reports which are easy to read and easy to understand. Our professional staff is also available to assist you in your inspection needs and to answer any questions you may have related to the inspection or consulting work we perform.
All of our reports and any associated photographs are made available online in an easy to access and secure Adobe Acrobat format for download and distribution.
Professional Engineering Inspections service area includes Houston and its outlying areas. We most frequently provide our services in the areas around Houston including Katy, The Woodlands, Kingwood, Baytown, League City, Friendswood, Pearland, Galveston, and Richmond. Upon request we will travel anywhere within the State of Texas and have provided our services to our clients in Austin, El Campo, Columbus, Brenham, Bryan, College Station, Corsicana, Dallas, Denton, and Livingston. If we must travel outside our normal service area we must normally charge a reasonable travel fee. Our travel fees are depended upon the time expected to be spent on site and distance to be traveled. If you live outside of the Houston area do not hesitate to contact our offices for a travel fee.
You are having your home inspected and your inspector points out that the cable ends are exposed at your foundation and you wonder exactly what this means. In short it means that the cable ends of the tendons that reinforce your foundation are in risk of eventual corrosion failure or possibly have failed. When tendons fail there is an increased potential for damage to the foundation concrete.
Let’s take a look at basically what a tendon is and why it is important. In post-tension reinforced slab on grade foundation systems the concrete is reinforced to prevent cracking by the installation of tendons in two directions with the purpose of inducing compression into the concrete as a result of applying tension on the cables of the tendons after the concrete has hardened, or cured. Since the concrete is now in compression in two directions it will resist cracks when it bends. Bending occurs due to loading by the weight of the structure, items placed in the building, or in our area changes in the volume of the soil supporting the foundation as the seasons change and the soil changes moisture content. To be clear the tendon is defined as the set of components typically including a steel cable housed in a plastic protective sheathing filled with grease, two cast anchor points at the ends of the cable, and the anchoring wedge at each anchor. This is the basic theory behind this type of concrete reinforcement.
Post-Tension reinforcing tendons are one of those structural construction elements that are “out of sight and out of mind” for most consumers. They are important and they do typically require some maintenance over the life of a foundation to prevent the ends from being exposed. When an engineer or home inspector points out that the cable ends of the tendons are exposed or damaged they are letting you know that the critical anchor point of the tendon is at risk of receiving water, which can result in corrosion of the cable, anchor, or locking wedges. Significant corrosion can cause the cable to lose its tension and leave the foundation concrete with insufficient compression to resist cracking.
Failure of a tendon is not always visible. During visible cases of failure, the cable of the tendon may extend out of the foundation after failure or in some cases may damage interior floors. This occurs because the cable actually stretches like a rubber band during tensioning and in service, and when the cable fails this stretch (which is stored energy) is released. If the release occurs at one end or the other it is much like flicking a rubber band across a room and results in the cable extending out the side of the foundation.
If you find your cable ends exposed you should contact a repair contractor familiar with the inspection and repair of tendons. They will expose the face of the foundation for cleaning and inspection of the tendon anchors. It is best to hire a company that installs and repairs tendons in the event you find one or more tendons in need of testing or repair. They should also be familiar with the correct detail and materials for proper repair and grouting at the tendon anchors. Keep in mind that most foundations have beams of concrete fabricated into the construction and some tendon ends are probably buried. Digging to expose at least two sides of the foundation will be necessary. In some cases it may also be warranted to expose other sides to check the other end of the cable, which should be sufficiently buried in the concrete of the foundation but can be placed close to the surface of the concrete and as a result left exposed as well.