Clay Pipe

[holidayinn]

Hi, I was digging up an area on my front driveway (grass) when I came across this clay pipe. I was digging to approx 20cm depth and found the pipe sitting higher closer to the house than it does to the pavement.

The pipe is supported by some crushed concrete/stone which I've left as is for now. There is a also a gap between adjoining pipes, I've looked into the gap and the pipe seems dry, only dirt is present.

I want to throw some MOT type 1 over the area and compact, then lay gravel. Do you think I'm ok to continue? Or should I dig deeper an find what the pipe is doing?

Ideally, I just continue the project as is, initial impression is the pipe isnt doing anything...but after some more experienced views.

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[holidayinn]

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[John D v2.0]

Maybe a redundant sewer or other drain.

You have 2 concerns now, one is that it might not be disconnected properly from the drainage system - check the downstream manhole to be sure. You don't want to make a nice habitat for rats.
The other concern is in case it collapses or settles and leaves a rut in your drive. That's pretty unlikely unless you park a lorry there, but if you wanted to be sure you could remove it completely.

 

[JohnD]

to my eye, the collars look fairly modern (not old brown salt-glaze) so may well be in use. I'd be thinking about rainwater or drive gullies. Follow it back upstream.

It would be very poor (but not unknown) for a foul drain to be so badly laid.

 

[holidayinn]

I thought soakaway, I'll try to check a bit further either direction but leaning towards burying it mainly due to time deadlines. It should (I hope) stay intact as I plan to lay some honeycomb plastic grids before the gravel which should displace pressure and only cars to be parked on top, unless I'm being too naive.

 

[John D v2.0]

Plastic grids won't really spread the pressure, you'd need a good thick layer >100mm of hardcore compacted to do that. I forget off hand the minimum depth for drains under drives, but for that depth in theory you'd have to lintel over it somehow or something to take the pressure off.
My concern would be you having to take up your drive one day in future to deal with an issue.

 

[holidayinn]

Thanks John, I do plan to put a layer of hardcore on top, but compacting might also break the pipe.

I agree, will try to spend some time digging further into the issue and see if I can track if anything is feeding into it.

Worse case scenario, I put this area back as was. Also, it's located pretty close to the fence so won't have the pressure of a car directly on top.

 

[Nige F]

to my eye, the collars look fairly modern (not old brown salt-glaze) s.

It's salt glazed- the rings round the end of the pipe are the giveaway, used to key the sand/cement joint

 

[Ian H]

The collar is broken off the first picture so you will easily be able to test if anything goes down it.

Is there a black pipe/ducting closer to the fence too?

 

[holidayinn]

I can't see any black pipe or ducting, the pipe sinks further below ground than I have dug (pavement side), it was only when I worked backwards towards the house I spotted it. It's sitting at an angle, sloping down from the house side towards the pavement and supported with some aggregate around it. What did you think it could have been?

I'm leaning towards - worst case scenario - pouring some concrete over the pipe, to give it some support and then hardcore, compact and then lay honeycomb + gravel.

I will try to check the house side of the pipe and also run the taps to see if I can detect any water going down at any point of the pipe.

 

[Ian H]

I think it's an old ducting and too shallow to be a drain. That's just a guess though and I'm jealous because I never get to work on pipes that depth

 

[Ian H]

I thought that black thing might have been something

 

[John D v2.0]

Ian Either your hand is tiny or the iPhone X is bigger than I expected

 

[holidayinn]

Thanks Ian!! You're right, it is something I stumbled on also. It's some black plastic trunking which was dug underground, contains a black wire which runs full length of the driveway. I think it's virgin media cabling (?), my neighbour has the same thing, although his wire is stapled to the bottom of my fence!! (I only moved into this property a few months ago).

 

[Ian H]

Ian Either your hand is tiny or the iPhone X is bigger than I expected

I've just had my nails done so my hand looks a bit girly