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

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The pipe will probably be 6" all the way.
Hmmm, the main shared pipe? Doesn't look that way from the (really bad) endoscope footage we have - looks like a really wide channel. I maybe try and cut down the footage & post it. We plan to put a proper go-pro down there with a torch on tomorrow before we fit the inspection chamber to get a proper look at things for future reference (in case we do need to take the concrete 'cap' off).
 
This is footage from the awful quality endoscope camera : starts facing the back wall (with the line along) then you can just see the circular collar (?) of the pipe downstream on the left; at the end of the video you can see the lip of the >6" clay pipe embedded in the wall. The pipe and channel seem quite wide to my untrained eyes.

(Edit : Oh my gosh I just re-watched that ... the compression from iMovie & youtube together has made it even less watchable! I've re-uploaded a version exported from iMovie with different settings... might be a bit better)

 
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Bear in mind these houses were usually built with 'combined' sewers, that took both foul and rainwater from the backs of the houses at least. During dry weather, flow was minimal, but during heavy rain, the drains would be at or near capacity. Therefore whilst each property may only be on a 4 or 6" pipe, the communal sewer taking a number of houses could be a lot bigger, 6 or 9" in some cases.

A good storm was factored into the design of earlier drainage, firstly to help wash the system through every so often, and secondly to help wash down the fields at the sewage farm, where it ultimately ended up.....
 
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Finally managed to get the IC installed yesterday.

Bailed out few inches of rainwater from trench...

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Squidgy clay... the kind that pulls your boots off...

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Cut collar off & removed cracked section...

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Covered end to protect joint surface & packed with newspaper to support pipe whilst mortaring (as suggested by wessex inspector - said that it should rot away harmlessly over time)..

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Mixed up Cementone Rapid cement (waterproof) - was a completely wet slurry with suggested amount of water, so had to add more powder to make it useable as a mortar (it seemed to indicate it wasn't advised to add sand)

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Tamped base of trench after putting some drier soil in to 'absorb' some of the clay sludge moisture. Tamped down 2 bags of 25kg 10mm gravel & created roughly level surface. Allowed us to step on it with boards without sinking in.

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We struggled to get the mortar around pipe to set ...possibly due to the low temperatures (?) - after an hour, we set up a heat gun on a low setting to raise the temp in the trench a few degrees!

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Hand mixed a semi-dry (?) concrete mix : 3 x 25kg bags wickes ballast, 1/2 bag of 25kg of blue circle cement (so 12.5kg) with 4L of water - this (hopefully) was roughly a 1:2:4 (cement/sand/aggregate) mix.

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Then we connected a 15° bend to the spigot of the pipe inserted in the >6" clay pipe in the manhole wall. This was a bit awkward, since the mortar was still not very well set & we wanted to avoid disturbing it by pushing the plastic pipe inwards & breaking the bond/seal between plastic & mortar. We considered using a Floplast/Flexseal bandseal coupling to remove the need to exert pressure in that direction (I made a last minute trip to B&Q to grab one just in case) ... however with trying to conserve space and get the IC as close to the manhole wall as possible, we decided to risk it and carefully ease the 15° bend on using plenty of silicone spray whilst holding the pipe spigot as tightly as possible with the other hand.

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We inserted a short 'rocker' pipe into the outlet of the inspection chamber, then slotted that into the 15° bend. We left a 10mm gap, so that when we inevitably slipped, the force would be taken up by that gap mostly, rather than the force being transferred straight into the pipe embedded in the mortar. We then bedded and levelled the IC on the concrete, packing in extra concrete in the voids around the edges - being careful to retain access to the inlets.

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It was getting very late by this point & so we've ended up with this amusing temporary drainage so we could have showers & use the loo!

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We will need to create a better rainwater solution (it is going to rain tomorrow) and some thought needs to be given to a potential backdrop shaft / drop shaft arrangement to accommodate the overly steep fall. I also have some ideas about how best to design/install things to accommodate a different main run in future. I would like to move bathroom to the front of the house, with an under-stairs toilet & possibly a side-return extension. I will start a new thread to discuss drainage consideration/designs related to that!
 
A clearer video showing what lies beyond the >6" clay pipe embedded in the brick wall. You were completely correct Ian - this is a covered over manhole! No idea if it was covered by the victorians when they extended the run (this house was built after the one immediately to the left, downstream) or whether a previous owner covered it.

Either way, it is currently under my garden - I am going to avoid removing the cap if at all possible - I have a large amount of plants on top & the garden (when there isn't a massive trench in it) is one of the only things keeping me sane whilst the house has been a building site with no plaster/floors etc for two years! :O I can see that some roots have penetrated the cap, although I suspect these are from the sycamore and another evergreen tree that were pretty much directly above, which I removed a year ago.

 
My new thread regarding the design of the rest can be found here if anyone is interested :)
 
The rats will love that no Interceptor trap and Roding eye to worry them.
 
The rats will love that no Interceptor trap and Roding eye to worry them.

Interesting - so you are of the view that interceptors deter rats? I thought most people thought that they would just swim through them.

I am very keen to avoid rats (my previous property got infested with them and it was a never-ending battle) ...but obviously interceptors seem to be quite prone to problems.

However, if you have any suggestions I'm more than happy to take them on board, bearing in mind the space limitations etc.

Personally I am concerned that the covered over manhole has lots of nice dry ledges for them to hang out on, but I can't really do much about that since it's the responsibility of Wessex.
 
You should have started off with a interceptor where you have connected to sewer then your manhole.
In your other post imo you should avoid all those y junctions and fit another manhole and bring all connections into it separately, also internal manholes are not a good idea, the interceptor manhole should be vented with a FAI and the other end of your drains vented via soil stack vent, this gives natural air flow through your drainage system.
Rats can get through the water seal, but not as easily as a open pipe, also the water seal prevents smells the same as your wc and sink waste traps.
Google interceptor traps not the type you had to start with.
 
You should have started off with a interceptor where you have connected to sewer then your manhole.

We are working in a very tight space - there would be no room for an interceptor and a manhole I doubt - its already encroached on where the extension was planned.

In your other post imo you should avoid all those y junctions and fit another manhole and bring all connections into it separately

The diagram with the y-junctions was my initial feeling of how things might have to be connected - however, I don't want to do that anymore since this will be a 'temporary' install until the bathroom is moved & the extension is built. A manhole here would seem maybe excessive (do you mean a small 290mm access chamber though?) - plus it would end up internal when extension is built, unless it is removed at that point - quite a waste of parts/materials for a few months of functioning drainage!

also internal manholes are not a good idea

From what perspective? From a sewer smell perspective (double sealed presumably would negate this assuming proper ventilation via stack) or are you thinking from an aesthetic perspective, or something else?

the interceptor manhole should be vented with a FAI and the other end of your drains vented via soil stack vent, this gives natural air flow through your drainage system.

I have to say, I'm quite amazed at how little problems there are with drain smells here - even when we have had blatant leaks & even open sewer! I am not sure what FAI stands for (i've tried to look it up) something (beginning with 'F') air intake I'm assuming...

Rats can get through the water seal, but not as easily as a open pipe, also the water seal prevents smells the same as your wc and sink waste traps.

So the water seal of a trap is merely a deterrence to rats, the smells should be prevented by traps at base of rainwater bottle gully, sinks, toilets etc, so can't see the point of doubling up there (when as I've mentioned the drains don't seem to smell much here anyway compared to other places I've been)... maybe a rat flap might be a similar level of deterrence since, you weren't around to offer your advise prior to us doing the work...

Google interceptor traps not the type you had to start with.

I have googled interceptor traps *endlessly* (how I worked out that mine is definitely a Buchan patented one, and that the Kernon and Beancliffe type patents are the ones most people think of when they say 'Buchan trap' or 'interceptor trap') - I suspect I have now read everything there is on the internet about them!

Yes I can see there are modern manufacturers of clay ones. However, the majority of individual opinions and modern regulations etc, seem to be that they are obsolete - a hangover from the days of belief in 'miasma', and cause way more problems with clogging than doing anything useful! I'd guess we would have to build maybe a brick manhole to fit the clay interceptor prior to it - there is not enough space really, without being at less than 45° from the base of the already shallow/sinking foundations. If there is genuinely good, proven reasons for installing something that keeps drain unblocking companies in good business, I'd love to find/hear the evidence, because so far you are the only person who has recommended one!
 
All these traps are best left in the past.

I've seen rats twice in 14 years of doing drains, once in Chester city centre and once behind a kebab shop in Bradford.

They are only a problem if they can escape the drain through a hole or break and then get into your cavity, not worth worrying about.
 

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