Hi

We would like to move our kitchen sink to an adjacent wall 4m to the
other side of the room. There is a large void under the kitchen that
should allow me to run the waste pipe to the large pipe (soil pipe?)
running down the corner of the house. I have two questions:
1) what angle does the new waste pipe need to be at?
2) the existing grey pipe that runs down the corner of the house, is
joined just under the floor to a short span of pipe (possibly ceramic?)
that leans away from the corner of the house, this is then connected to
90 degree bend (not plastic, possibly ceramic?) which is then connected
to to a pipe that appears to run almost horisontally out of the house
wall. Is it possible to connect the small sink waste pipe directly into
the ceramic pipe? If so how? If not, do I need to replace the short
span of ceramic pipe with a plastic one? How messy will that be?

The house was built in 1981 if that helps.

Many thanks
Pete