Copper pipe

So the castle went ok today. The two Greeks were pushing me to finish as they want the floor down but at 3pm I told them I needed to work alone as they were confusing me. They're nice chaps but limited English.

So, putting copper pipe in the wall & sand/cement over.

I'm sure I saw 15mm pipes wrapped in something or is there something I can wrap it in?

Is there another way other that plastic pipe?

Cheers all