Industry in general uses an enormous variety of rotating machinery, the greater number of which are mounted on some type of concrete foundation, or plinth. Frequently, the amount of time and effort spent on the design and construction of the foundations, and on the allimportant interface area between machine and foundation, does not seem to be commensurate with the value of the installation as a whole.

Many problems directly attributable to the foundation size and shape, or to inherent weaknesses in the concrete material, have been noted over the years. Mechanical problems have arisen from the inability of the foundation to operate as a good vibration damper. Problems related to the the use of unsuitable grouting materials are also frequently seen.

This paper attempts to examine some of the main problems affecting machinery foundations, and to point out some repair procedures that have worked well. It also points out the importance of properly designed and constructed foundations, and the desirability of using polymer based machinery grouts.