Installing a toilet downstream of another

[floodwarning]

Hello, I'm reworking our ensuite which is next door to the main bathroom.

I want to connect the new toilet into the existing soil pipe which runs directly under it.

See the picture below for the layout.

Can I simply put a strap boss on to the existing soil pipe or is there anything I should be aware of?

1. Do I need an AAV and where should it go?

2. I don't have space to put a swept connection in on the new toilet, it'll probably have to be a 90° connection into the horizontal soil pipe. Do I need to put some sort of backflow preventer to prevent stuff from the new loo sitting in the pipe between the two loos?



Thanks in advance, I really appreciate any guidance

 

[oz-plumber]

you don't need anything you mentioned - except for a swept junction.
not good for a pan connection at 90 degrees

 

[floodwarning]

you don't need anything you mentioned - except for a swept junction.
not good for a pan connection at 90 degrees

Cheers oz-plumber, good advice. I've ordered one of these sh*t shoots:

I'm sure I'll be on again soon with more Billy basic questions. Appreciate the help, cheers