Replacement drainage run

[davidm]

Good afternoon. To cut a long story short, I've done some excavation after a drain report highlighted some problems, and I've decided to rip out the old clay pipes and brick inspection chamber for my mid-terraced property, and replace completely with 110mm plastic - the total distance from SVP to party wall is only about 7m. The existing IC is at the head of a run serving 4 other houses before connection to main sewer. I've been informed that the MH on my property is my responsibility. Currently the set up is simple: SVP and gully on separate pipes for a couple of metres then joined via branch connector. This single pipe then has short sections of pipe joined to form a 90 degree bend into brick IC the outlet pipe of which runs under the party wall to the neighbouring property.

I'd like to neaten up the installation (boss kitchen waste connector, below ground rainwater connection. The service is combined foul/rainwater and the maximum depth to top of existing pipe is about 650mm (much shallower near to existing gully/SVP). At the party wall, depth is about 700mm max to top of existing pipe (150mm I think). WC connection is directly under party wall and I'll cap off when this work is done. I re-instated the WC to provide 'facilities' in the interim.

The question I have is whether or not to have a new configuration. Diagrams I've seen on various websites shows shallow inspection chambers used as branch connectors. My new design features:

a) replace the brick IC with 450mm and and pull it back about a metre to comply with having access at change of direction;
b) use all three inlets on a 250mm shallow IC to combine waste from SVP, gully and a new rainwater connector, as a replacement for the branch connector. Short run then from outlet of 250mm to inlet on 450mm

Or just run 3 separate pipes a longer distance straight to 450 chamber?

I guess another way of putting it is: how would you recommend connecting up if this was a new build or extension?

Many thanks in advance for any help/opinions.

Kind regards,

David Morton

[Tony McC]

Is this on a combined system? You mention the possibility of putting a RWP in with the SVP, which shoukld only be done with a combined system or when there is absolutely no alternative.

This is a big ask: can you provide a simple diagrammatic sketch of what you envision?