Hi,

I am just about to start preliminary work prior to installing an en
suite in my bedroom next to the bathroom.
ATM the toilet has a connection through the wall onto an old cast iron
soil pipe going into the garage floor (garage extension built onto side
of house by previous owners).
The pipe from the toilet goes through the cavity wall and (viewed inside
the garage) bends right onto another cast iron "T" where a plastic vent
pipe has been inserted to vent through a tile on the side of the garage
roof.
It looks like this:

Plastic | |
|| ||
_______| |
toilet ( )_______ | ** Cast Iron
| |
|| ||
| |
| | Cast Iron into garage floor

What I intend to do is to replace the cast "T" and pipe to toilet with
plastic and to fit a cross pipe connector (sorry don t know exact name)
ready to drain shower/basin about one metre to the right of "**".

Hope you got the "drift"!

Now the questions.
1. How easy is it to get the old "T" off without breaking the collar of
the pipe going down the wall.

2. What diameter pipe must I use from the basin/shower?

3. I assume I can fit the new plastic junction and cut out the relevant
holes later or cut it and fit a blank?

4. If I have to cut the old pipe (because I damaged it), is there a
neat way of connecting plastic as the only way I have seen is an orrible
rubber "gator" thingy!?

Thanks