Dave,

Thanks for that but isn't it just a strap for connecting a 40mm pipe to
a 100mm stack?

I want to connect my toilet waste to a vertical stack, so I'm after a
100mm connection.

Charlie

You'll need a branch, so you'll have to cut out a section of stack, insert
the branch and then use a slip coupler to join the bottom of the branch to
the existing stack (this is a coupler where you can slide it all the way
down below the cut out section and then slide it back up once the new branch
is in place. If there's no room above ground for the levels to work out,
then you'll need to dig out the stack below ground. Is this the case?

You'll end some silicon gel and a rasp or some such for chamfering the edge
of the cut pipe. I'm assuming you have plastic soil pipe of course.

Alistair