How to Check if a Concrete Floor Has Post-Tension Cables

Post-tension cables are steel cables that are sometimes placed in concrete when the concrete is poured onto a structural foundation. The cables help stabilize and reinforce concrete against tension pressures such as pulling forces. These forces can be caused by excessive weight on the concrete slabs causing sagging, which creates pulling pressure on the slabs. Depending on the application in which the concrete floor is used, post-tension cables are required instead of rebar. Detecting if post-tension cables are used is useful if you see signs of structural damage or safety concerns.

Things You'll Need

• Metal detector

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Instructions

1. • 1

     Clear the concrete floor of any furniture or metal objects such as filing cabinets, tool kits or tables.

   • 2

     Turn on the metal detector. Turn it to about halfway on the sensitivity setting.

   • 3

     Hold the metal detector so the sensor pad on its bottom is hovering a few inches above the concrete floor.

   • 4

     Move the detector back and forth in a slow, sweeping motion while walking across the concrete floor. Since there are likely to be a number of tension cables underneath, the detector should immediately begin beeping to indicate the presence of metal.