Relocate pipework

[Nwwps]

hi

Wondering if someone could advise, I have a property that needs all the external drain pipes relocating. you.can see the network of pipes on the photo attached and I would like to move all these pipes on the adjacent wall at the rear running them inside the rooms and boxing them off. The house was an old Mill with 2.5ft thick solid brick walls. Is there any problem moving the main vent stack using a pipe to slope towards the main drain.
you can see the wall is tapered to strengthen the building for the water wheel is there a problem with running the vent stack along this at the rear .adjacent

 

[SimonG]

Those pipes are tatt. Any changes will only improve. It a'int gonna get any worse than that.

 

[Best]

If you want to follow the angle of the tapered wall of the house, you could do that vertical part by either using a bend of the same angle (that might be hard to get in above ground soil pipe fittings) or turning horizontal just above the tapered part you could then use a 90 degree (actual 87.5 degrees) bend to turn to the tapered wall vertical angle drop. Remember that to follow that angle will mean you will need to then do something below ground with it - most likely immediately sideways using a 90 bend to initially follow parallel to house wall.
That old stack looks like it might be partly cast iron, which will need care removing it. Very heavy and dangerous stuff!

 

[Nwwps]

My main concern is, if there is a bend at the bottom of the vertical drop will effect the flow and block up. The cast iron pipe will drop off no one underneath.

 

[Best]

A bend at bottom of the stack will be fine. Even if you needed to add a second 90degree bend it still would be okay. The part of the stack will get a right heavy wash of water down it by gravity, so rarely could block and only then if somebody stupidly flushed an object down the loo like a nappy, or sanitary towel etc.
Obviously keep flow where possible as easy and uninterrupted route - by using a 135 degree bend for example below ground if you where going from A to B.
Install a rodding connection on the stack just above ground if you wish and also have a manhole at each junction and corner of the house so you could rod the sewer at any place in the future.
You would be advised to contact building control for any sewer alteration and they probably will need a plan of new sewer layout (if different) and perhaps an inspection
Put some weak sand and cement mix just below the first underground bend to support the bend.
That cast iron pipe is really heavy and could pull you off a ladder, so be careful with it.
I had to take some down and the builder erected scaffolding just to help remove it

 

[SimonG]

Could also add in an access t to rod it if it blocked.

 

[Nwwps]

Thanks for the advice, I will add the rodding conection like you said might not be a requirement but would prefer to make sure no problems will occur the long run, and will make sure the cast iron pipe will not get me like a felling a tree. Please if anyone has some more pointers before I start let me know, virtual beers all round