Are these drain pipes old clay? Would you change them if you were me?

[Matt723]

Hi All

Considering re-tiling the pathway at the front of the house however before putting anything new at the surface we want to make sure whatever is below is sound so we don't have to break the new if we need to fix the old pipes later. We lifted the sanitary cover and saw the below photos.

We know that toilets and sinks run through the bottom pipe, which is about 1.5m deep. The top one we are not sure, it may be for run water since there is a rain water drain at the back of the house which we don't know where it goes.

Are those pipe old clay, those that are prone to cracking? If yes would you change them, would it be very difficult? Are there any other viable alternative than replacement such as epoxy lining?

Any pointer gratefully received. We will have a professional survey shortly but would love to have some info so I know what to walk into and ask the right questions when the guys are onsite.

 

[mrrusty]

Undisturbed salt glazed clay pipes will last just about for ever. Unless you have evidence of problems, leave well alone. That all looks good to me.

 

[Mottie]

They look fine to me. When Thames Water replaced our (pitch fibre) drains last year, they used clay pipes instead of plastic. I asked why and they said it was because they were stronger.

 

[stuart45]

You can't tell without a drain survey, or borrow a camera. If you've never had a problem, they're probably OK. Salt glaze should be surrounded by concrete, but ground movement can damage the sand/cement joints.

 

[Ivor Windybottom]

The fact that it's so deep would be enough reason for me to leave well alone. If it aint broke then don't fix it.

If it ever cracks or leaks under your posh new paving then an epoxy liner can be applied to it in-place without any digging. It's basically a long soft tube that is inserted from the inspection chamber into the pipe. An inflatable sausage is put inside it, pressing it into the pipe walls while it sets hard.

Get your paving done and don't worry about it.
If any of your neighbours' "produce" flows through it then it's the water company's problem to fix it if there's ever an issue, and to make good if they have to disturb your paving.

The only interesting oddity are the lengths of diagonal iron bar. One's already rotted and gone somewhere. If you ever get a backing-up loo then have a look, you may find that one of the others has fallen in. Does anyone know what their purpose was?

Edit: Are they a ladder? If so then they're not structural, perhaps chopping them off might be a sensible precaution? Against future blockages and anyone using them as a ladder and breaking their leg when they snap.

 

[Ivor Windybottom]

I should add that your new paving must still allow access. Hopefully you already know this and weren't actually thinking of sealing over the chamber lid. You could use one of those tray chamber lids if you want to tile over it so it's less visible.

 

[stuart45]

Edit: Are they a ladder? If so then they're not structural, perhaps chopping them off might be a sensible precaution? Against future blockages and anyone using them as a ladder and breaking their leg when they snap.

That's what they are. Normally you build proper step irons into the brickwork, staggered to allow for easy access.

 

[foxhole]

Replaced run of clay pipes during extension work , Thames water insisted on clay replacement .

 

[Ivor Windybottom]

Our 1950s clay pipes were leaking at every joint and had lots of cracks. I replaced them all with plastic, in which I have much more confidence. Clay is strong but very brittle.

I also replaced a 50m pipe run across a field with ribbed twinwall plastic. This is as used under roads, motorways etc. Plastic seems to be the preference for public works these days from what I've seen driving past many roadworks.

Our ground is about 1m of topsoil on top of sand, so is probably unusually prone to movement. Clay just doesn't have enough flexibility to cope. But within solid clay, both are probably fine.

 

[boringoldcodger]

The top one we are not sure

My guess is that the top pipe was originally installed for ventilation, but (obviously) could be used for other things.
I reckon you've got a Buchan Trap (I expect there are other names/makers); is there always water in the outlet? If so, that's a U bend and above the outlet there's a second pipe, in which there's a plug. That plug can be removed when the U bend blocks to allow water to flow out whilst you're fixing the blockage.
Where I live we have a Buchan Trap and there's a similar looking upper pipe connected to a vent.

 

[mrrusty]

I reckon you've got a Buchan Trap

Every day's a school day!! https://www.blockage.co.uk/interceptor-traps/

 

[ree]

FWIW: salt glaze pipes and modern clay pipes are different animals in a number of ways.

 

[Matt723]

FWIW: salt glaze pipes and modern clay pipes are different animals in a number of ways.

Hi Ree, how are they different, is one preferable to the other?

 

[Matt723]

My guess is that the top pipe was originally installed for ventilation, but (obviously) could be used for other things.
I reckon you've got a Buchan Trap (I expect there are other names/makers); is there always water in the outlet? If so, that's a U bend and above the outlet there's a second pipe, in which there's a plug. That plug can be removed when the U bend blocks to allow water to flow out whilst you're fixing the blockage.
Where I live we have a Buchan Trap and there's a similar looking upper pipe connected to a vent.

I must say I don't understand all you are saying here however you are quite right that there is always a bit of water in the outlet a bit like in a toilet and yes there is a vent similar to this one and it could very well be linked to that pipe above as you say! We were thinking of removing the vent and cementing above it.

Is this a Victorian soil pipe vent?

Hi, I've got some awful pointing that needs attention on an 1890 house. There's a strange device, that I've never seen before, connected to the combined foul/surface drain: Is that what the Victorians used to vent the foul gases from the pipe? Or is it something else altogether? Can...

www.diynot.com

 

[noseall]

I must say I don't understand all you are saying here

Have you even looked at mrrusty's post and the link?

What you have is an old interceptor trap. It's a hangover from the Victorian era. We have a better understanding now and SVP's.

Your drains are unfeasibly deep. Have a long hard think before you decide to do ANYTHING with them.