How to connect to 6" old clay collar? - SOLVED

[Undaunt]

After having discovered a broken 'buchan trap' that has been leaking for goodness how long (beginning to dig created an effectively open sewer / cesspit in our garden!) we have been dithering about design but have today decided to go ahead, disconnect all our foul water, remove the broken trap & connect a new inspection chamber to the clay pipe beyond.

Unfortunately where we had expected to find a 160mm old clay pipe with enough protruding from the main shared sewer that we could cut into using an angle grinder & attach a 6" clay to 110mm plastic adapter.... we have found that there is simply a clay collar protruding, then the brick sewer wall immediately behind.

Anyone have any clever ideas of fittings that we can use to connect to this? Bear in mind it is the larger (6"?) clay pipe socket, which probably makes it even more awkward. Or is it a case of contact Wessex water & explain the problem?

Of course we were hoping to get the inspection chamber in today & rig up a temporary soil pipe dropping into it so we could have working plumbing again, so the quicker our solution (without bodging it) ...the better.

Any help or advice gratefully received.

 

[Undaunt]

The brick wall is the side of the shared sewer, there is a gap in the mortar joint & the pipe at the bottom of the photo is actually part of the Buchan trap /p-trap to hence is not a straight section of pipe that we can create a spigot out of.

 

[Nige F]

We need more photos further away - is the trap outside the manhole

 

[Undaunt]

Hi Nige, thanks for taking the time to respond. There was never any manhole at all, it is a victorian terrace built in 1890 and pretty much nothing has ever been done to it, so no modernising of the underground pipework & no manhole.

We have taken down the old outside toilet on the back 'leg' of the terrace off the kitchen & traced the unused pipe section back from that. Moving away the house to the sewer, it changed from 4" to 6" (badly jointed!) and then there was a y junction where we presume the other run of pipe from the 'side return' area joins on.

The trap is approximately 2.8m from the back wall of the kitchen, between the y-junction and the sewer (approx 3.2m from back wall of house), and had a vertical 'stack' above it which had been covered with tiles & buried. Our trench turned into a cesspit once we had carefully exposed it! :/

We have identified it as being a Buchan trap (despite a knowledgable friend not recognising it - it is fairly rare for them to still exist nowadays) - the victorians apparently installed them to prevent 'miasma' coming up via the sewers which they wrongly believed caused cholera etc. They are notoriously problematic as I understand it - ours was completely cracked in more than one place (house opposite was bombed in the war - possible shockwave damage?)

Overview shots :

We plan to replace all of the drainage back to here :

I have other plans for an extension & moving the bathroom to the front of the house in future (so our design between the inspection chamber & house needs to take that into consideration) ...but for now we are trying to address the more pressing issue of leaking drains, that may be contributing or causing the extensive damp and subsidence to the rear of the house.

 

[Undaunt]

A quick sketch model of the original drainage (some known, some deduced/guessed).

• The yellow section was a clay pipe from the outside toilet in the 'lean-to' and we traced back from this unused section.
• The pink bit was where the pipe changed to a 6" clay pipe (it was literally slotted inside with no mortar and the 6" pipe was cracked)
• The red bit is the y-junction & the dark red circle is the vertical stack on top of the Buchan trap.
• The turquoise section is still buried so we have assumed its layout - it may have more bends than shown.
• The grey bit is the presumed shared sewer (no plans exist for it from the water board) - a year ago I found a concrete/stone cap around 1.5 m wide when I was digging the flower bed on the right.

 

[Undaunt]

Just an update - we are now awaiting a visit from Wessex Water who said they would send someone round in 4 hours (they are very busy, so we are sat here twiddling our thumbs 5 hrs later with no foul drainage!)

 

[Undaunt]

So clearly there was a miscommunication... Wessex Water sent round a guy from dynorod, who was quite surprised & confused by the situation!

Sawdust in a bucket it is for tonight then!

 

[Undaunt]

The lean-to with the outside toilet before we dismantled it all... note the truly 'outside' toilet!

 

[Hugh Jaleak]

I will assume that socket, going into the brickwork in the first picture, is 6". If you can remove the old pipework, leaving a clean socket, one of these, (if you can find one!), https://www.mytub.co.uk/hepseal-ad-s-s-adaptor-150mm-sa2-2-product-574238 should fit it, (ideally with rubber O ring fitted to make the seal).

From the spigot end of that you may have to use a 150-100mm Supersleve clay fitting, then from the 100mm end of that, fit a Supersleve to plastic adaptor, and carry on in plastic from there.

Otherwise I'm afraid it is going to be a case of bodging it a bit. If you can get hold of a piece of 6" salt glazed to replace the Buchan trap, (you'll have to do a traditional rope and mortar joint into that socket), then come off the spigot end of the new section as required.

Plenty of Interceptors and/or Buchan Traps still out there, the Victorians believed 'Drain air' was the cause of illness, and so by sealing off the house drains from the main sewers, using interceptor traps, they would protect people from this 'drain air'. Instead, they fitted a low level early type of Air Admittance Valve to the last chamber before the main sewer, where the interceptor was located, with the idea that air passing over the top of the soil stack would draw air into the low level vent, through the house drainage system, thus ventilating the house drains. The main sewers were ventilated by means of large cast iron vent columns in the street.

 

[Ian H]

You could mortar a plastic 6-4 into the collar.

One time (in an emergency). I used an AC4000 with the clay end jubilee clips removed. I tightened the 4" end onto my plastic as normal and then the end which would normally go over 4" clay fitted tight inside the 6" clay.

Give me a minute and I'll take a pic of similar.

 

[Ian H]

So 6" pipe > AC4000 > 4" pipe

To this:

Fits nice and tight

And you will be able to use your drains and loose that awful tash

 

[Ian H]

Delete this one.

 

[Undaunt]

Ok, so Wessex Water say this is not their responsibility and are unable to advise for legal reasons. They are suggesting I contact a private drainage firm since they think it is my drainage that is a problem (although it seems that the clay pipe is part of the shared sewer wall & we cannot replace it without disturbing that wall). I explained that the people I've tried speaking to so far mainly just clear blockages and do rodding etc, so I've asked for & been emailed a list of approved contractors, who I now plan to contact.

Thankyou for those suggestions above, those are interesting ideas & could well work.

I just wish McAlpine did a 6" version of this which could slot inside without worrying about the collar : https://mcalpineplumbing.com/plasti...nectors-roof-flashing/dc1-blc-drain-connector ...although I don't think they are technically designed to be used underground. I have no idea why Floplast or Wavin etc don't do something with a similar design that can slot inside a clay pipe rather than those band seal type couplings (the one we've used before from Toolstation was a bit rubbish for getting a good seal with!) ...I would have thought something with internal fins would create the best seal & be much easier to install. In this situation it would be a godsend!

 

[Undaunt]

Hugh - thank you so much for this. Do you think that the Hepseal Ad S/s Adaptor 150mm Sa2/2 : (https://www.mytub.co.uk/hepseal-ad-s-s-adaptor-150mm-sa2-2-product-574238) would need to be mortared in or would the rubber o-ring be sufficient?

 

[Undaunt]

Ian - I'd never thought of using one of those bandseals connectors inside a pipe - Im surprised they fit so well & create a decent seal that way! Good to know & definitely an option we will look at. I guess there will be a couple of ridges inside, but hopefully nothing to cause too much of a problem.

And I agree about the mustache... but he won't listen to me about it.