Cracked Soil Pipe and New Proposed Design Advice Please

[onabudget]

Dear All,

I have attached some drawings the left one shows the current setup and the right one shows the planned layout. I'll be going to see the BCO once I've made some better drawings but can you help me with the following questions please.

The old soil pipe is not usable as it's cracked over time and shifted with some building movements, it's all concreted in and impossible to fix or even get an adapter onto it, as you carve out the concrete surrounding it the pipe cracks more hence the idea to add an external soil pipe.

This has the advantage as providing a point of entry for a top floor on suite to be added later.

My question are

1) Would you try and Tap into the existing line going to the sewer the distance from the back wall of the house to the sewer is only 1.5 metres or would you fit the new plastic line all the way into the sewer?

2) Where should I run the new soil stack, maybe a daft question but the toilet is in an L shaped bathroom so it needs to sit in the middle of the wall, the soil on the outside can go anywhere on the outer wall to join up to the chamber but should I fit a boss onto the end of the stack that goes straight through the wall 'A' on the diagram i.e. behind the stack pipe (my concern is the join will be in the wall) or should I put the stack offset to where I want the toilet waste and then run along and then through the wall then turn 90 to connect up to the toilet. It would give more room for adjustment and make lining everything up not so difficult to start with

3) How deep does the foundation to sit the rest bend on have to be.

4) The house does not have deep footings so I may be forced to have the rest bend higher than I would like as the footings spread out, this would mean the fall on the pipe would be more than wanted but over such a short distance 1.5 metres would this matter?

thanks

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[noseall]

It is the slightly uglier solution but i would go for off setting the vertical pipe and have a 90 degree bend rather than a branch directly into the loo, unless you are super-confident of the final loo position.

We would consider how difficult and what the condition of the pipe is running into the shared sewer. In a majority of cases, particularly if B.C. are involved, then we would 'graft-in' an inspection chamber on the sewer.

Don't worry about the height of the rest bend, it may cause some splashing in the chamber should you fit one. It is purely myth that steep falls leave the solids behind.

 

[Hugh Jaleak]

I'll second Noseall on the soil pipe arrangement. The drain position will probably determine the soil pipe position, and you really want to avoid bends in the vertical 'wet' part of the stack. The junction and branch can be fitted to suit the pan position.

I'd run a new length of plastic to the chamber if getting a connection to the existing drain is proving difficult. A bend is permissible immediately outside a chamber, useful if you need to offset the drain run slightly. Break out old pipework, fit new to suit and make good as necessary. (A foul branch should discharge at an angle in direction of flow.)

 

[onabudget]

thanks guys, I had not thought about a chamber but I'll now measure up and work out the depths and take some pictures then post back on this thread to see if you have any more great advice or if it looks ok. Thanks for your help and have a great xmas