What's this 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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tonyh66

its a drain, shouldn't have a gap in it though.

holidayinn

Thanks, I'm assuming as it has a gap and there appears to be nothing but dirt within it, it's non-operational? The pipe was already covered with soil and grass, I plan to replace soil with MOT type 1 and gravel.

I'm leaning towards just carrying on with the project unless I should be looking into this further?

minicooper272

Agree with the drainage pipe idea. It's possible the pipes dry because the gaps are letting water leach out into the ground.

I would just suggest trying to follow the pipe back to wherever it starts - it's so shallow, but after you bury it it'll be harder.

TheCyclingProgrammer

Soakaway possibly? Where is it running from?

holidayinn

Initially thought it served as a soakaway/gully, it seems to be slanted lower towards the pavement and higher towards the house, hence it seems dry as it's not rained for a while.

I'll have to remove some slabs and check more thoroughly as to where it's coming from. I'll also try to check the downstream manhole.

Still leaning towards burying it due mainly 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.

EachPenny

Just because it is dry doesn't mean it isn't in use

I'd go with minicooper272's suggestion of trying to find out what it does now, rather than discovering a problem later.

It looks like the gap has been created when the collar of the pipe got broken. The hole, and any others like it, need to be carefully covered before backfilling.

When you compact the type 1, make sure you don't put too much pressure on the pipe - if it is that shallow it can easily get broken.

The same applies if you are going to use the area for parking - a very shallow pipe can easily be broken by the weight of car tyres. If the pipe is not redundant I'd think about protecting it with some paving slabs (any old second-hand ones will do) bedded on sand, or else lay some concrete about 2 inches thick over an area about six inches wider than the pipe on either side. Then put the type1 and gravel over the top. It sounds like a lot of extra work, but is far easier than having to dig it all up again to repair a broken pipe which by the time you notice will probably be full of type1 as well

Edited to add: I've just seen the additional post... honeycomb plastic grids will help a bit, but don't underestimate the pressure exerted by a car tyre on top of a fragile clay pipe.

minicooper272

Pour water down a few drains and see if it appears.

Do cars park on it just now, or is it a new driveway? The reason I say to trace it is because it's so shallow, and if you're changing the load on the pipe, it could damage it & you want to know where it might back up.

holidayinn

Thanks all, agree better to spend some time and look into it now while it's partially exposed rather than fear the unknown.

It will be a new driveway, if it becomes too troublesome to follow I could just lay soil back on top (as was) and border it off. It's pretty close to the fence so won't have the weight of a car on top.