Adding soil pipe to existing outside drain

[GC1971]

Hi all
I’m converting my basement into a studio flat, and was originally going to macerate the waste and pump it away.
I’ve since found out that there is a soil drain cover and gully outside the studio flat door; so I’m now going to kango a trench in the floor to go to this point for all my waste inc. the WC.
I’ve never done any plumbing, and would really appreciate any advise on how to go about the actual plumbing of this all.
I assume I need some sort of access point by the WC to rod if required; -and not to just go into the soil pipe; -is this right?
Also I have a shower, 2 sinks & a washing machine to drain. Do I just run all these in series, gradually increasing the pipes ODs into the soil pipe in the floor?
If so, what size pipes should I use?
For your info it goes W/Machine – Kitchen sink – Bathrim sink – Shower and there is only about 1.5m between them.
Cheers for any help.

 

[powell30]

You need to contact your local buildings control officer first. Connecting underground drainage is notifiable work. Thay are helpful so chat through what your proposing but be warned, if you go ahead and they find out you may end up digging it all up.....even if you have done it right as they will need to SEE you have. Plus, you will need the required paperwork for when you sell to prove work complies

 

[GC1971]

Ah, -right you are; thanks.

 

[JohnD]

and have a look under that cover, try and work out the existing routes. If you poke something down the pipes you will get an idea of direction and distance to nearest bend.

I used a 3m length of plastic conduit last time I did it, it mustn't be anything that could break or get stuck.

 

[GC1971]

Ok, good idea.
Do I need to propose a plan to building control? ie know what I'm going to do before I call?