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Build Over Agreement on Existing Extension Rejected Pitch Fibre Pipe

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Some context: I bought a terraced house recently which has an extension on the rear. My surveyor recommended improving the extension, in particular one wall.

So I have got planning permission to improve existing extension. I have instructed a structural engineer, but pipes were not within the scope as we had no idea. I have instructed an architect, more for insulation purposes as building control require this.

Upon digging the foundation for the new wall, a pipe was found. Building control asked for a build over agreement with Southern Water. The builder asked myself and architect to go ahead with this. In the meantime, he built a bridge over the pipe and continued with the wall (expecting a pretty standard approval, I guess).

This was in fact rejected after a CCTV survey due to the pipe being pitch fibre.

The solutions given were firstly to reduce the size of the extension. This isn't feasible as it would remove the entire extension and considering I bought this house with the extension, because it had an extension, It'd obviously be a very expensive option for me.

The second option is to relay the pipe with manholes either side where the pipe has been relayed. This is also not feasible as it would involve demolishing the extensions concrete slabs (with layer upon layer of steel) and additionally, the extension sits side by side with both neighbours extensions who also have structures built over the pipe and there is minimal space between extensions for access or to fit a manhole.

I want to contest this, as the most feasible option in my opinion is to make sure the bridge built over the pipe is overpowered and to mention that this extension has been in situ since the 90s and there has been no damage to the pipe.

I would assume the next alternative if they refuse would be to divert the pipe. This would require diverting from one neighbours garden, around my extension and back down to my other neighbours garden. I don't know if anyone would have an indication of costs if this were the case. Assuming the diversion would be about 3m one way and potentially 10m across.

In regards to contesting the rejection, would anyone have advice? Or perhaps even prior experience regarding pitch fibre pipe build over rejections?

Any help would be great.
 
An existing and proposed plan might help, just a sketch will do, include the drain runs.

Your builder is a ding-bat who should have sought advice when he found the pipe, it says in black and white that pitch fibre may not be acceptable to build over, arguably the surveyor SE & architect are also idiots for not considering if there was any drainage. Its usually very obvious where drains run in terraces.

I'm not sure what you hope to contest, (their) pipe needs to be able to cope with jetting etc.
 
The projected life of pitch fibre drain is around 40yrs, so I'd check to get an idea of age. If near to 40yrs, I'd contact the pipe's owner (Southern Water?) and offer them free unhindered access to replace their pipe in return for rerouting it. Often a little compromise pays big dividends.
Just a word of caution where PF drainage is concerned, it was sometimes made with asbestos fibres.
 
Some context: I bought a terraced house recently which has an extension on the rear. My surveyor recommended improving the extension, in particular one wall.

So I have got planning permission to improve existing extension. I have instructed a structural engineer, but pipes were not within the scope as we had no idea. I have instructed an architect, more for insulation purposes as building control require this.

Upon digging the foundation for the new wall, a pipe was found. Building control asked for a build over agreement with Southern Water. The builder asked myself and architect to go ahead with this. In the meantime, he built a bridge over the pipe and continued with the wall (expecting a pretty standard approval, I guess).

This was in fact rejected after a CCTV survey due to the pipe being pitch fibre.

The solutions given were firstly to reduce the size of the extension. This isn't feasible as it would remove the entire extension and considering I bought this house with the extension, because it had an extension, It'd obviously be a very expensive option for me.

The second option is to relay the pipe with manholes either side where the pipe has been relayed. This is also not feasible as it would involve demolishing the extensions concrete slabs (with layer upon layer of steel) and additionally, the extension sits side by side with both neighbours extensions who also have structures built over the pipe and there is minimal space between extensions for access or to fit a manhole.

I want to contest this, as the most feasible option in my opinion is to make sure the bridge built over the pipe is overpowered and to mention that this extension has been in situ since the 90s and there has been no damage to the pipe.

I would assume the next alternative if they refuse would be to divert the pipe. This would require diverting from one neighbours garden, around my extension and back down to my other neighbours garden. I don't know if anyone would have an indication of costs if this were the case. Assuming the diversion would be about 3m one way and potentially 10m across.

In regards to contesting the rejection, would anyone have advice? Or perhaps even prior experience regarding pitch fibre pipe build over rejections?

Any help would be great.
100% of the time we encounter either old salt glaze (or worse) pitch fibre pipes beneath an extension footprint - we replace them with modern plastic and an IC, one end or the other.

Your builder is an idiot and has cost you thousands. The pitch fibre can't stay as it's rubbish. Even worse than salt glaze.
 
The second option is to relay the pipe with manholes either side where the pipe has been relayed. This is also not feasible as it would involve demolishing the extensions concrete slabs (with layer upon layer of steel) and additionally, the extension sits side by side with both neighbours extensions who also have structures built over the pipe and there is minimal space between extensions for access or to fit a manhole.
We managed it (twice) and it can be done...







Both jobs have the IC right up against the boundary. You can see the remnants of the old salt glaze in the latter images.
 
Age is the ever-present defect built into of PF drainage. By offering free access now, negates any problems in the future so both parties' benefit.
No, the water company will merely say if you want to build over it you pay for it's replacement or diversion. Or the homeowner won't get BC sign off.
 

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