Soil pipe keeps leaking

[JT101]

Hi guys

I have a soil pipe that won't stop leaking

In the original photo you can see there were 2 cracks in the cast iron pipe. When the drain got blocked, the water nearly backed out out the 1st floor toilet, and leaked through these cracks. Previous person put an ill fitting flexible coupler on the pipe.

We called out a local company who charged us £150 to try plunging the toilet (which obviously we'd done ourselves), and gave us a quote for £1500 to bring in some serious machinery to unblock the drains underground.

Rather than pay that, we cut out the damaged section of pipe. If you look at my diagram, you'll see you can't rod it around the elbow, nor from the manhole which slopes in the opposite direction.

So with some OneShot, and rodding the small section we could, eventually it seemed to release.

I replaced the pipe with plastic, socket at the top, and a securely fitted flexible coupler below.

Checked the toilet, and it flushed fine

4 weeks later, same problem, and it's also leaking out of that flexible coupler now!

So the questions are:

1) What else can I use on that lower joint to stop it leaking? I definitely tightened up the jubilee straps on there. I can't see how a slip coupler would be any better, especially since the cast iron and plastic are slightly different diameters

2) Is there any powerful equipment I could hire to blast out the drain, given the awkward arrangement underground which is all buried under concrete?
I do have access to a Karcher K5, but obviously the gun won't fit far down there. Are there any attachments I could buy? Not sure it will be powerful enough. I could borrow a friends Nilfisk

Thanks

 

[Hugh Jaleak]

I'd put money on the issue being at the bottom of the stack, either the rest bend at the bottom of the stack, or not far from that, the underground clay pipework has collapsed.

Jetting it with a pressure washer attachment may buy you some time, but really I would advise it needs proper investigation. May be able to get a smaller CCTV camera in from the top, down the stack and have a look what's going on at the bottom/under the concrete, but be prepared that you might have to start digging.....

 

[blup]

Its backing up as said.

 

[JT101]

Was referred to a family run company in Canterbury rather than the shysters we employed before. Definitely seemed more on the ball, and went straight in there with a drain camera.

First thing to note I had got the drain layout wrong. They said the manhole ran a straight line, under the building out to the main road, connecting to the main sewer. The vertical soil pipe dog legged at 90 degrees from what I previously said, connecting into that line from the manhole. Which all makes sense.

When they looked at the bend, they could see what looked like a shard of material, that just wouldn't budge. They cleared the blockage, and said we'd probably be ok if we only use 2 ply toilet tissue. Bamboo and recycled toilet paper causes more blockages.

The only permanent solution is complete excavation and replacement of that bend at a cost of £2800.

Interestingly they said that often the cast iron soil pipe, which connects into the old clay pipes in the ground, swells and splits the clay elbow, and this could be the shard of material we saw.

For now we'll use the 2 ply loo roll and see how it goes.

Thanks for all your help guys

 

[Hugh Jaleak]

Oh good grief, sounds like you've found another bunch, did they arrive on Horseback? Solid matter, and be it 2, 3 or 43 ply Bog Roll will soon block it again if there is a foreign object wedged in the drain.

Clay to cast joints often do fail, as there is no flexibility in them, and slight ground movement over the years is enough to cause damage, but nearly £3K to dig it up and replace? You've already done half the work, by replacing a section of the cast stack with plastic, how deep is the underground run from the bottom of the stack?

 

[JT101]

I would say about 800 - 1000mm