Kitchen Sink Problem

ac198179

Jeepers_Creepers said:

As 2'penny says, the quick re-blockage was likely just the lumps of loosened fat regrouping at a bend or narrow section.

Are you absolutely CERTAIN that the sink isn't slowly draining into one of these inspection holes? Is there any possibility that the test flush you sent down there isn't being held back and trickling through so slowly that you didn't register it? Perhaps time to add some dye?

Worth, I think, working through it all again from scratch - with a cuppa and a piece of paper. Sketch a plan of the house and the location of all the drains and gulleys and whatsits that you are know of. Do all of these ultimately serve one single sewer wot runs out of your boundary? Now the kitchen and sink - is that in the same place it was before the extension was built? If yes, then which obvious route would the waste have taken out what was the exterior wall? And what obvious route would the underground drain have taken from there to get to the main sewer on your property? Is there a sensible reply to this? Is it "It must shooorley have gone from here to that manhole"?

And did the CCTV company work back from that manhole towards the kitchen?

What do you have on the ground immediately outside the extension wall - is it a concrete path, gravel, lawn? Ie - could it be easy dug up? If all else fails - if a drain inspection still draws a blank - I think I'd rather dig up a path than a floor.

Where is this 'rodding point' the previous owner mentioned? Outside (hopefully..) or in the kitchen floor? Does its 'location' fit in with a sensible straight run between the kitchen sink and a manhole?

Finally, can you claim for this work on your insurance?!

Apodemus said:

Lots of sensible advice already on here.  I would wonder if it was worth sucking out the 12 Litres as before and then add caustic soda, otherwise you have a huge dilution factor and unlikely to achieve much.  I'd also be thinking about whether there is an option for a test trench outside so that you can find and access the pipe without lifting the floor, then install  a rodding eye at that point for future use.

GDB2222 said:

One other option is to install a macerator under the sink and then run a new waste through the house and into the drain somewhere convenient. Horrible things, so a last resort really, but they will pump the waste a long way horizontally, or even upwards if needed.

Thanks for the further comments & advice people! To answer a few of them, I've done a thorough "survey" myself and the kitchen sink definitely doesn't drain into the manhole/inspection chamber outside. Although every other sink/toilet etc does. The drainage company that have been out already didn't CCTV from the outside for this reason. I've actually got another tradesperson coming to have a look next week, he's an underground pipers/drains specialist who installed us a new water wipe a few years ago to replace an old iron pipe. I've thought about a macerator, but would still need to lift the floor to run new pipes etc.

ryan7

Maybe I have missed something but does the pipe under the sink go into a U-bend before  disappearing beneath the floor boards?
Also if you need to go under the floor, do you have to remove the flooring? 
Is it not possible to remove the kitchen unit without disturbing the floor or are the units built on top of the tongue'n'groove? 

Jeepers_Creepers

ac198179 said:

Thanks for the further comments & advice people! To answer a few of them, I've done a thorough "survey" myself and the kitchen sink definitely doesn't drain into the manhole/inspection chamber outside. Although every other sink/toilet etc does. The drainage company that have been out already didn't CCTV from the outside for this reason. I've actually got another tradesperson coming to have a look next week, he's an underground pipers/drains specialist who installed us a new water wipe a few years ago to replace an old iron pipe. I've thought about a macerator, but would still need to lift the floor to run new pipes etc.

When the original CCTV guys did their inspection, I presume - for the distance they were able to pass the camera - they could tell in which direction the waste pipe was going? Are there any clues at all about where this mystery pipe goes?!

Really don't know what to suggest, unless the drain guy has some very aggressive chemicals available to him that will quickly dissolve grease and other stuff.

ac198179

Jeepers_Creepers said:

ac198179 said:

Thanks for the further comments & advice people! To answer a few of them, I've done a thorough "survey" myself and the kitchen sink definitely doesn't drain into the manhole/inspection chamber outside. Although every other sink/toilet etc does. The drainage company that have been out already didn't CCTV from the outside for this reason. I've actually got another tradesperson coming to have a look next week, he's an underground pipers/drains specialist who installed us a new water wipe a few years ago to replace an old iron pipe. I've thought about a macerator, but would still need to lift the floor to run new pipes etc.

When the original CCTV guys did their inspection, I presume - for the distance they were able to pass the camera - they could tell in which direction the waste pipe was going? Are there any clues at all about where this mystery pipe goes?!

Really don't know what to suggest, unless the drain guy has some very aggressive chemicals available to him that will quickly dissolve grease and other stuff.

ryan7 said:

Maybe I have missed something but does the pipe under the sink go into a U-bend before  disappearing beneath the floor boards?
Also if you need to go under the floor, do you have to remove the flooring? 
Is it not possible to remove the kitchen unit without disturbing the floor or are the units built on top of the tongue'n'groove? 

I've been told that chemicals/acids won't do the trick, that the blockage is probably too bad. And I've already tried all the different ones that you can get in the supermarket.
In terms of the pipes, under the sink there is a bottle trap, this then drains down vertically into a pipe which goes about 1 metre across to the left under the cupboards (there is an incline, this has been checked). It then goes forward into concrete which is under the dining room floor. I've attached a picture. The point where it disappears into concrete is under the tongue and groove floor which is glued down! This flooring is the one that you can see in the bottom right of the picture. The kitchen cabinets sit on top of this too!

Apodemus

A few random additional thoughts....

Is it possible that the pipe doesn't actually go to a sewer at all, but simply goes to a soakaway?  The implication being that you perhaps don't have a pipe blockage, but a clogged/silted-up soakaway.

I'd still want to give an aggressive chemical a try without the dilution factor of a pipe-full of water, ie adding only chemical after sucking out the 12L that is contained in pipe and gully.  I'd suck out the 12L then replace it with 3 or 4L of caustic soda. I know your drain company has said that the blockage is too bad - but they don't actually know anything about the blockage, as they've not reached it.

If the built-over gully was once outside, can you envisage how the pipe-run might have been laid out before the extension was built?  I guess the options would have been: straight line from gully to sewer; straight line from gully to inspection/collecting chamber; 90 degree right along outside wall; 90 degree left along outside wall.  Do any of these options give new opportunities to find the outfall?

grumbler

Apodemus said:

Is it possible that the pipe doesn't actually go to a sewer at all, but simply goes to a soakaway? 

Absolutely impossible. It's not rain water. And the gully that they reached apparently is another sign of sewage.

ac198179

Apodemus said:

A few random additional thoughts....

Is it possible that the pipe doesn't actually go to a sewer at all, but simply goes to a soakaway?  The implication being that you perhaps don't have a pipe blockage, but a clogged/silted-up soakaway.

I'd still want to give an aggressive chemical a try without the dilution factor of a pipe-full of water, ie adding only chemical after sucking out the 12L that is contained in pipe and gully.  I'd suck out the 12L then replace it with 3 or 4L of caustic soda. I know your drain company has said that the blockage is too bad - but they don't actually know anything about the blockage, as they've not reached it.

If the built-over gully was once outside, can you envisage how the pipe-run might have been laid out before the extension was built?  I guess the options would have been: straight line from gully to sewer; straight line from gully to inspection/collecting chamber; 90 degree right along outside wall; 90 degree left along outside wall.  Do any of these options give new opportunities to find the outfall?

grumbler said:

Apodemus said:

Is it possible that the pipe doesn't actually go to a sewer at all, but simply goes to a soakaway? 

Absolutely impossible. It's not rain water. And the gully that they reached apparently is another sign of sewage.

I've given it a lot of thought, spent ages studying the plans from the extensions & alterations that have been done and I can't fathom it out. Where the sink is & where the pipe disappears used to the outside wall of the house- a long long time ago though (house was built c1938). I have wondered if it has indeed just been connected into a surface water drain or a soakaway. I know it shouldn't be done and is illegal, but I'm wondering if it is a possibility? 

Apodemus

grumbler said:

Apodemus said:

Is it possible that the pipe doesn't actually go to a sewer at all, but simply goes to a soakaway? 

Absolutely impossible. It's not rain water. And the gully that they reached apparently is another sign of sewage.

I'm not sure you can reach that conclusion.  The house was built in the 1930's and the requirement to link to the sewer was part of the Public Health Act which came into force in 1937 - which is around the time that the OP reckons the house was built.  It is not uncommon to read of housholders unearthing old cess pools, or simple collecting chambers that drain to soakaways, immediately behind their house.  If the Act was in force at the time of construction, it may not have been at the time that the design was approved and even then, the phenomenon of builders cutting corners is not new.  We don't really know much about the gully and it doesn't necessarily point to it linking to a sewer - well designed rainwater systems have gullys, even if they then go to a soakaway.

I agree that a soakaway is unlikely, but it is not "absolutely impossible". 

ryan7

1) either the pipe away from the sink is block
2) the pipe that disappears under concrete has been compromised/fractured/broke in someway that's getting blocked by waste or rubble. 
3) the original waste gully pre extension is still being used and is blocked and you have no access. Again this area maybe compromised and the surrounding load underground keeps blocking it even after being drained. 
Have you tried using hard chemicals that can't be purchased in store?
I can recommend one shot drain cleaner.
Are there any neighbours with similar build and no extension whereby you can view their kitchen waste pipes?
I'd be temped to have a plumber cut away the pipe that disappears into the foundations and have a look with camera's and lighting. He can easily replace the pipe he cuts away. 

ryan7

 

To have got 12litres out a 4mm pipe makes me think the blockage must be fairly deep and not on the surface. What do others think?
The original suction has drained the fluids but not remedied the actual problem.