Could someone please tell me who oversees the plumbing contractor to make sure that Foam Core PVC is not used under a concrete slab? Are there any inspectors involved who check the accuracy of the plumbing work? In a previous message I was told that Charlotte Schedule 40 Foam Core PVC is fine to use in a new custom house, but it is not to be used under the concrete slab. There is Foam Core sticking up from the concrete slab. What do we do next?