Kitchen waste though wall of extension

[Porthole]

Hi there

 

Be really grateful for your help on this one. We are in the middle of building an extension and the builder is doing the waste pipe for the kitchen sink. The sink will be on the kitchen island and he has put the waste pipe through the wall of the extension. He has done this by punching a hole (not drilling a circular hole) through the extension blockwork low level and poking the sink waste pipe through the hole and filling the gap with foam (see photo below). The floor of the extension where the kitchen will be is block and beam.  I'm not sure if this is correct. In the past, we had to build over a public sewer and had to lintel over it obtaining a build over agreement from Thames Water. Although this isn't a public sewer, I would have thought the principles would be the same. Can someone please advise, so I at least have some knowledge before confronting the builder. Many many thanks.