The maximum thickness that can be tested using Impact Echo depends on many factors, but it is normally related to the quality of the concrete and...

The maximum thickness that can be tested using Impact Echo depends on many factors, but it is normally related to the quality of the concrete and the selected impactor.

Normally, the backwall is clearly visible in structures up to 60cm, but in some cases, we can extend this value up to 80cm. Note that Impact Echo is meant for plate-like structures (minimum length > 6 * thickness): walls, slabs, etc. And it does not always provide readable results for slender elements such as columns or beams.