I like foam
We have to admit, the sight of expanding foam oozing out looks quite amusing. But this is far from being the right solution, let alone providing a good seal. Who wants an unprofessional construction of this kind in their utilities connection room? It is an open door to the ingress of humidity and the radioactive noble gas radon.
A better approach:
Correct sealing is vital in preventing the ingress of water and radon as well as meeting the statutory framework conditions. We therefore insist on the MSH Basic FUBO for building entries through the floor slab.