The product is only as good as the surface prep, which is 99% of the success/fail of this product. We have had great success with it on our new pools, but we have had an occasional issue with delamination on a sun ledge for instance if the surface had a spot that was missed in the roughing up or the application of the epoxy etc. Some concrete /plaster mixes are also not quite mixed all the way, resulting in an area that has a harder time with adherence and the chemical process that happens in the top layer of the surface for both a mechanical and chemical bond.