I have recently fitted an additional bathroom to our new home which includes a saniflo unit. This needs to link to our stench pipe which is my final connection.
The existing pipe is of cast iron type construction. Can I drill into it to accept the new pipe or should I replace the stench pipe in favour of a plastic one?

Hi Steve,

Let's get togather on terms so we're on the same page. A dry stench pipe is called a vent stack while one that accepts waste discharge is called a stack vent.
You have two outlets on your unit to connect. The discharge outlet goes to a stack and the other runs to a vent.
Which one are you asking about? Regards, Tom