There is a growing need for non-destructive techniques capable of investigating civilengineering structures of concrete material. The Impact-Echo (IE) method is one suchtechnique based on the study of a resonant and stationary mode. This mode corresponds to a Lamb mode. In turn, this accentuates that the IE method can easily be extended to include the analysis of propagating Lamb modes as well. Thereby a quantitative evaluation of the elastic plate properties and thickness is possible. Moreover, the use of Lamb waves lay the foundations for extended analysis which makes measurements based on an extension of the IE method an attractive complement to current ultrasonic techniques for plate-like concrete structures.