Underground Drainage

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I'm in the process of adding a second W/C to my bungalow (the one circled in purple in the layout plan below) which is being installed in what is the end of the attached garage.

There was a 110mm underground soil pipe already in place which served a washing machine and the condense from the boiler (which has since been relocated), this pipe ran parallel to the wall immediately above it (from the perspective on the layout plan) into a T-section near the internal door. I have revised this layout slightly to remove the effective immediate 90 degree turn in the T-section, by relocating the pipe further away from the wall, and adding a 45 degree triple socket and 45 degree joint instead as per the photo 1 below. (The photo shows what is to the right of the purple circle in the layout plan).

Photo 1:
IMG_9756.jpg


The soil pipe then goes off under the kitchen floor.

From probing with a camera, it makes two 45 degree turns to the right, then flows out under the kitchen into the garden, before doubling back on it self around three more 45 degree turns into an inspection chamber located in the garden as shown in photo 2 below (and central blue circle in the layout plan - above the green circle). This then flows back out under the kitchen, and reappears outside the property inside another inspection chamber in what is a shared private driveway down the side of the building where it flows off into the public foul sewer in the road.

Photo 2:
IMG_9754.jpg


Photo 3:
IMG_9750.jpg


I've added a stack pipe to the side of the new toilet (photo 3), which I'll take up and vent out the roof, I will also add rodding access to it, which I'm confident would allow good access from this end should it ever block, but I'm concerned about the part in the garden which doubles back, and if it would be best to install another inspection chamber at that point (green circle on plan and in photo 2), along side the other? As rodding from the existing one around what is a 135 degree turn could be problematic?

Ideally, I would simply reroute the new toilet straight out into the pipe running down the side of the bungalow, but given this would involve digging up land I jointly own with my neighbours and would no doubt cause inconvenience to them in the process, I'm seeing if it can be done from within my own boundary.

I realise this is quite complex to get your head around, but would appreciate your thoughts.

Thanks for your time.

Layout:
11bd.png
 
Last edited:
I would install the additional Chamber as per your Drawing, although this does really need to be run past Building Control who will have the final say.

I am also a little worries about the leg from the Junction to the Stack, will this be dry or are you planning on making a Connection to it? Risk of solids collecting and causing an issue if it remains dry.
 
I would install the additional Chamber as per your Drawing, although this does really need to be run past Building Control who will have the final say.

I am also a little worries about the leg from the Junction to the Stack, will this be dry or are you planning on making a Connection to it? Risk of solids collecting and causing an issue if it remains dry.
It will have waste from sink and basin draining in it.
IMG_9750.jpg


Grey vertical stack goes through roof to open vent. Potentially may use for bathroom upstairs in future works.
 
It will have waste from sink and basin draining in it.
View attachment 425889

Potentially may use for bathroom upstairs in future works.
Would swap the Boss Pipe out for a Rodding Access, ideally any cleaning can be done from the Proposed new Chamber outside, but belt and braces doesn't hurt, and I think I'd trust a Screw cap internally over one of those Rubber things you can retrofit.

Go into the Stack with the Basin/Sink waste slightly higher if you can, regs frown upon any connection less than 450mm above the invert of the drain at the base of a Stack.
 
It will have waste from sink and basin draining in it.
View attachment 425889

Grey vertical stack goes through roof to open vent. Potentially may use for bathroom upstairs in future works.
Make sure that WC swept bend connection is far enough away from the wall, not to be a problem. Looks to me like your new wall surface start point will be off-set further away from the existing wall, because of all the boxing in etc.
 
I'm in the process of adding a second W/C to my bungalow (the one circled in purple in the layout plan below) which is being installed in what is the end of the attached garage.

There was a 110mm underground soil pipe already in place which served a washing machine and the condense from the boiler (which has since been relocated), this pipe ran parallel to the wall immediately above it (from the perspective on the layout plan) into a T-section near the internal door. I have revised this layout slightly to remove the effective immediate 90 degree turn in the T-section, by relocating the pipe further away from the wall, and adding a 45 degree triple socket and 45 degree joint instead as per the photo 1 below. (The photo shows what is to the right of the purple circle in the layout plan).

Photo 1:
View attachment 425882

The soil pipe then goes off under the kitchen floor.

From probing with a camera, it makes two 45 degree turns to the right, then flows out under the kitchen into the garden, before doubling back on it self around three more 45 degree turns into an inspection chamber located in the garden as shown in photo 2 below (and central blue circle in the layout plan - above the green circle). This then flows back out under the kitchen, and reappears outside the property inside another inspection chamber in what is a shared private driveway down the side of the building where it flows off into the public foul sewer in the road.

Photo 2:
View attachment 425886

Photo 3:
View attachment 425888

I've added a stack pipe to the side of the new toilet (photo 3), which I'll take up and vent out the roof, I will also add rodding access to it, which I'm confident would allow good access from this end should it ever block, but I'm concerned about the part in the garden which doubles back, and if it would be best to install another inspection chamber at that point (green circle on plan and in photo 2), along side the other? As rodding from the existing one around what is a 135 degree turn could be problematic?

Ideally, I would simply reroute the new toilet straight out into the pipe running down the side of the bungalow, but given this would involve digging up land I jointly own with my neighbours and would no doubt cause inconvenience to them in the process, I'm seeing if it can be done from within my own boundary.

I realise this is quite complex to get your head around, but would appreciate your thoughts.

Thanks for your time.

Layout:
View attachment 425880
Why isn't the cloak suite going straight out of the back wall? You don't want to put an IC (green) right where you might want a step.
 

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