Kitchen Sink Problem

ac198179

We have a problem with our kitchen sink blocking up, it's been going on since we moved into the house (nearly 6 years ago) but has gotten a lot worse recently. At first an occasional plunge every couple of months fixed it, but now it's blocking up again literally an hour after plunging. We've had a drainage company in to take a look and they managed to clear the blockage using a wet vac, but the problem recurred after only a day.

Unfortunately there is no external access to the drain - the house has been re-modelled several times since it was built (not by us) and there is now a rear extension between the kitchen and the garden. A 40mm waste pipe goes from under the sink and into the concrete floor of the rear extension.

From looking at the extension plans the drainage company believe the waste pipe goes into an original gully which has been built over without any access being provided to it. The drainage company have attempted to CCTV it, but it's hitting a water filled bend which they think is the blocked gully.

They've said that our only option now is to lift the flooring (which is solid wood tongue and groove boards, possibly engineered wood) and dig through the concrete floor to find the gully. Lifting the floor would be a big job just on its own - it would have to be lifted from the edge of the room and be lifted several metres across the room to where we think the gully might be. I've been advised that any jet washing/hosing etc from inside the house down the 40mm waste pipe would likely end up soaking the kitchen resulting in the floor having to come up anyway. Are there any other options out there? 

grumbler

ac198179 said:

I've been advised that any jet washing/hosing etc from inside the house down the 40mm waste pipe would likely end up soaking the kitchen resulting in the floor having to come up anyway. Are there any other options out there? 

Well, if there is a proper membrane under the concrete floor, then I don't see why the wooden floor can be affected. However you can expect anything from such a botch as an extension built over 40mm(!) pipe and a gully(!).

frogglet

grumbler said:

ac198179 said:

I've been advised that any jet washing/hosing etc from inside the house down the 40mm waste pipe would likely end up soaking the kitchen resulting in the floor having to come up anyway. Are there any other options out there? 

Well, if there is a proper membrane under the concrete floor, then I don't see why the wooden floor can be affected. However you can expect anything from such a botch as an extension built over 40mm(!) pipe and a gully(!).

I think they mean from splashback if the gully is very blocked.
Have you tried rodding it?
Also  what did they suck out the drain?
Was it soil ?
Kitchen sink drains can get years of fat blocking them.

grumbler

How can you rod a gully? I think jet is the only way.

ac198179

frogglet said:

grumbler said:

ac198179 said:

I've been advised that any jet washing/hosing etc from inside the house down the 40mm waste pipe would likely end up soaking the kitchen resulting in the floor having to come up anyway. Are there any other options out there? 

Well, if there is a proper membrane under the concrete floor, then I don't see why the wooden floor can be affected. However you can expect anything from such a botch as an extension built over 40mm(!) pipe and a gully(!).

I think they mean from splashback if the gully is very blocked.
Have you tried rodding it?
Also  what did they suck out the drain?
Was it soil ?
Kitchen sink drains can get years of fat blocking them.

Yes, it's splashback that they're concerned about. Because the only access is through the 40mm pipe, and there are a couple of bends, it's not possible no rod. The wet vac sucked out about 12 litres of liquid which had plenty of lumps of fat in it and was very smelly! After sucking they then used the wet vac to blow and after blowing was then nothing to suck. No more than 24 hours later the sink was backing up again!

Niv

One thing you haven't mentioned is if you have tried using a chemical to unblock the pipe? If it is a long way along the route I am not surprised the plunger is unreliable. I would be using caustic regularly for a while if i were you to see if that had any effect.
Also are you militantly strict on what you are putting down the sink? Even liquid oil should not go down there. What ai suspect may be happening is you are partially unblocking it then blocking it back up again with what you are putting down the sink

ac198179

Niv said:

One thing you haven't mentioned is if you have tried using a chemical to unblock the pipe? If it is a long way along the route I am not surprised the plunger is unreliable. I would be using caustic regularly for a while if i were you to see if that had any effect.
Also are you militantly strict on what you are putting down the sink? Even liquid oil should not go down there. What ai suspect may be happening is you are partially unblocking it then blocking it back up again with what you are putting down the sink

Yep, you wouldn't believe how much I've spent on various different potions, all to no avail! And yes, we're very careful about what goes down the sink, even more so now. Honestly it was working perfectly after the wet vac, they even left the hot tap running on max for 20 mins before they left to check it was OK. Then the next day it started backing up again!

FreeBear

Sounds very much like the drainage in my kitchen. Also had issues with a blockage... I was fortunate that there is a rodding eye over the pot gully and the waste pipe entered via a pipe at the back. But with it all being hidden behind/underneath kitchen units, access is next to impossible..

In the long term, your only real option is to lift the flooring around the gully and investigate what is below - You may be able to get away with just cutting out a 100mm square of the flooring and chiselling out the concrete to gain access to the top of gully. Once exposed, you can then make a decision on what to do in the long term so that it can be cleaned out periodically.

Niv

ac198179 said:

Niv said:

One thing you haven't mentioned is if you have tried using a chemical to unblock the pipe? If it is a long way along the route I am not surprised the plunger is unreliable. I would be using caustic regularly for a while if i were you to see if that had any effect.
Also are you militantly strict on what you are putting down the sink? Even liquid oil should not go down there. What ai suspect may be happening is you are partially unblocking it then blocking it back up again with what you are putting down the sink

Yep, you wouldn't believe how much I've spent on various different potions, all to no avail! And yes, we're very careful about what goes down the sink, even more so now. Honestly it was working perfectly after the wet vac, they even left the hot tap running on max for 20 mins before they left to check it was OK. Then the next day it started backing up again!

What concerns me most about that then is it could be soil coming in. I cant see how it could block so quickly otherwise.

ac198179

Niv said:

ac198179 said:

Niv said:

One thing you haven't mentioned is if you have tried using a chemical to unblock the pipe? If it is a long way along the route I am not surprised the plunger is unreliable. I would be using caustic regularly for a while if i were you to see if that had any effect.
Also are you militantly strict on what you are putting down the sink? Even liquid oil should not go down there. What ai suspect may be happening is you are partially unblocking it then blocking it back up again with what you are putting down the sink

Yep, you wouldn't believe how much I've spent on various different potions, all to no avail! And yes, we're very careful about what goes down the sink, even more so now. Honestly it was working perfectly after the wet vac, they even left the hot tap running on max for 20 mins before they left to check it was OK. Then the next day it started backing up again!

What concerns me most about that then is it could be soil coming in. I cant see how it could block so quickly otherwise.

Yes, I'm worried about that too - collapsed clay pipe or something?

goldfinches

You may already have done this but did they suck and blow from both ends or just from one if you see what I mean. Years ago I had a blockage and had to have the Dyn*rod chap out to rod it.
He explained that he would have to go into the road and rod from that end as well and that this was worth doing because coming at it from the other end and a different angle often did the trick because of odd corners and bends and so on.
Anyway the upshot was that he recovered a pair of underpants which had snagged on something and were then causing everything else to drain very slowly so that was that.
Where the underpants came from I've no idea, they weren't mine so must have come from further up the road and then got washed into the opening to my drains.
So if you can afford it it might be worth having them back to have another go but obviously there are no guarantees.