That's an interceptor - like a giant " U bend " under a sink. Those things can block even without silt getting into them . The outlet - with the open pipe above the channel - faces the road. So you can work out where the air inlet pipe goes to.
Insurance have declined drain/drive way claim
- Thread starter indus
- Start date
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Go to screwfix and buy some drain dye:
https://www.screwfix.com/p/monument-tools-flourescein-drain-dye-133g/31595
Put some in each toilet and then flush and see if you see the water flow in that manhole.
Andy
https://www.screwfix.com/p/monument-tools-flourescein-drain-dye-133g/31595
Put some in each toilet and then flush and see if you see the water flow in that manhole.
Andy
Hi Nige
I've googled interceptor pipe and done some reading. If it is indeed an interceptor pipe would that make it an integral part of my sewage system as opposed to 'redundant' as the insurers are claiming?
Thank you
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Sorry Ian, not sure if that question is directed at me and I'm not sure I've understood it. This is the pipe that is under discussion....
Thanks
Stand by the manhole and get someone to flush all toilets and open all the taps.
Does water run through?
Andy
Does water run through?
Andy
Unfortunately I don't have the tools to lift the manhole cover....
I could buy some if I can figure out which size I need!
The Pipe is question (at the top of the chamber) would be a Low Level air inlet. When the system was built, the house drain system was probably sealed off from the Main Sewer in the road by means of an 'Interceptor' as previously discussed. To ensure adequate Ventilation of the House drains, an Air Admittance Valve was fitted connecting to the last manhole before the boundary, and would have terminated with a metal 'box' on the top, with a grille on the front and a one way flap inside. (See here: https://www.diynot.com/diy/threads/sewer-drain-ventilation-advice-required-please.297016/ )
The working principle was, air passing over the top of the soil stack vent would cause a negative pressure in the house drainage system, thus drawing air in the low level vent and ventilating the system. However, the flaps invariably stuck open after years of use, and many had these air inlets removed as they were causing a stink by allowing foul air out, as I suspect has happened here. Given the amount of sand that has been displaced, it has to beg the question if you've a rodent issue in the system, and they've been looking for a way out, only to find they've been beaten by the Paviours.
First thing I'd do, is block the vent off inside the manhole with a good plug of decent concrete, then see about getting roots removed and driveway made good. I would also advise, your system is very likely to be classed as Private up to the point it passes under the Boundary into the road, (unless at least one other property is using it.) It this instance it is your responsibility, the Water Company will have no interest.
The working principle was, air passing over the top of the soil stack vent would cause a negative pressure in the house drainage system, thus drawing air in the low level vent and ventilating the system. However, the flaps invariably stuck open after years of use, and many had these air inlets removed as they were causing a stink by allowing foul air out, as I suspect has happened here. Given the amount of sand that has been displaced, it has to beg the question if you've a rodent issue in the system, and they've been looking for a way out, only to find they've been beaten by the Paviours.
First thing I'd do, is block the vent off inside the manhole with a good plug of decent concrete, then see about getting roots removed and driveway made good. I would also advise, your system is very likely to be classed as Private up to the point it passes under the Boundary into the road, (unless at least one other property is using it.) It this instance it is your responsibility, the Water Company will have no interest.
Thank you very much. Would you say that this air inlet pipe is an integral part of my system or redundant? As mentioned, the insurance company is declining the claim on the basis that the pipe is 'redundant'.
Much appreciated.
It's redundant now I'm afraid, times and technology have moved on. The Victorians were paranoid about 'Drain Air' believing that to be the cause of many ills, (until they found out it was actually contaminated water from the wells), and so designed in ventilation to their drainage systems. The Main sewers were often ventilated by by cast iron vent stacks, some of which still exist.
To be quite honest, if the only point of root ingress currently is via that vent pipe, then remove the roots and block it off. Get someone to relay the driveway, (and £4.5K is daylight robbery, you want that bit repairing not a complete new drive!), and remove the roots from around the chamber.
I would also strongly recommend you look at the source of the roots too, if there is a large tree nearby, it'll still be looking for water, and if one source is removed, then it could sink roots down further and break into any weak spots in your drains, causing a whole new world of pain....
To be quite honest, if the only point of root ingress currently is via that vent pipe, then remove the roots and block it off. Get someone to relay the driveway, (and £4.5K is daylight robbery, you want that bit repairing not a complete new drive!), and remove the roots from around the chamber.
I would also strongly recommend you look at the source of the roots too, if there is a large tree nearby, it'll still be looking for water, and if one source is removed, then it could sink roots down further and break into any weak spots in your drains, causing a whole new world of pain....
sometimes, on an old iron cover, the "keyholes" are broken and you can hire a lifter with an electromagnet that grabs the lid, and allows you to wheel it away. Don't know what they cost.
You can often lift a lid with a spade.
The OP has a recessed cover containing block paviours, to match the rest of the driveway. Believe me, there is no way that's coming up without the right keys, they weigh a tonne....
Pics 3 & 4 show blockwork subsiding upper left and upper right of the manhole:
The RH subsidence is above the "redundant" pipe.
This pipe may have collapsed because of roots finding or forcing a way into the pipe to locate water.
Blocking up the outlet with a bung or packed semi-dry will do nothing for saving the pipe further back if the roots continue to open joints & collapse the length of the pipe.
The Auger report says "all the other pipework was working satisfactorily". Was it - see below?
Auger also mention " minor joint displacement" - if that displacement allows water out or roots & soil in then its no longer minor.
The LH side subsidence?
Presumably its a collapsed drainage pipe.
If so, what is it draining? Where is it coming from?
Given its odd position in relation to the manhole how would it feed into the manhole - does it tee into the pipe that feeds into the manhole inlet? Or does it somehow end up as the manhole inlet pipe?
It could even tee into the lateral below the manhole?
How come that there's no mention in the report of this pipe or the damaged pavers above the pipe?
The latest pic shows what appears to be an interceptor trap - only the bung/plug is missing from the rodding inlet.
OP, What is the cause of the green tracking of algae to the right of the man hole?
OP, do you have a drainage map and a copy of Auger's video?
The RH subsidence is above the "redundant" pipe.
This pipe may have collapsed because of roots finding or forcing a way into the pipe to locate water.
Blocking up the outlet with a bung or packed semi-dry will do nothing for saving the pipe further back if the roots continue to open joints & collapse the length of the pipe.
The Auger report says "all the other pipework was working satisfactorily". Was it - see below?
Auger also mention " minor joint displacement" - if that displacement allows water out or roots & soil in then its no longer minor.
The LH side subsidence?
Presumably its a collapsed drainage pipe.
If so, what is it draining? Where is it coming from?
Given its odd position in relation to the manhole how would it feed into the manhole - does it tee into the pipe that feeds into the manhole inlet? Or does it somehow end up as the manhole inlet pipe?
It could even tee into the lateral below the manhole?
How come that there's no mention in the report of this pipe or the damaged pavers above the pipe?
The latest pic shows what appears to be an interceptor trap - only the bung/plug is missing from the rodding inlet.
OP, What is the cause of the green tracking of algae to the right of the man hole?
OP, do you have a drainage map and a copy of Auger's video?
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