Odd shower and sink drainage issue

[MasterMark]

Hello all!

I recently moved into a new (ground floor) flat and have a bizarre plumbing issue I was hoping someone might be able to shed some light on.

The bathroom has a toilet, basin, shower and separate bath. The toilet seems to flush ok, the bath drains fine. The sink and the shower, however, different story.

Shower – drains terribly. However, I’ve discovered a “fix” – if I plunge it while it’s running (one proper, hard plunge is all that’s needed) there’s a satisfying “whoosh” sound, the water suddenly drains and the shower then drains absolutely fine for as long as it’s running. Every day is the same, so there’s obviously nothing physically blocking the drain, clearly an annoying issue.

Sink – also drains terribly. Has one of those push/spring-loaded drain-stoppers. So the water is running, the sink is filling up. I turn the water off, it drains horribly slowly. If, however, (after the water has stopped running) I depress the drain-stopper, just for a second or so, and then release it, it then drains much more quickly (almost normally). If I do this trick while the tap is still running, however, it doesn’t really work very well. I’ve dismantled the trap below, cleaned it, put it back together, but no change. Like the shower there, there’s clearly nothing physically clogging up the pipes.

Does anyone have any ideas about what could be causing this issue, and how I might go about sorting it? Any help would be much appreciated!


Thanks!

Marc

 

[buck51]

sagging waste pipe holding water.

 

[MasterMark]

Thank you Buck51. the sink is next to an external wall, so flows straight outside. the shower drain is partly runs under the floor of the bathroom before taking a different route out. given they are both affected, does this mean the problem of the waste pipe is outside? or will I have to take the shower apart to access the pipework beneath?

 

[kbdiy]

Can you see the pipework on the outside? How/where does it run? Pictures might help.

 

[MasterMark]

Thanks, kbdiy.

I’m not at home but will take pictures tonight and post.

Regarding Buck51’s comment on the sagging waste pipe – what I don’t understand is why plunging it would then allow it flow freely. Is it because at the end of the shower, there isn’t sufficient gradient, so the water is held within the pipe. On starting the shower afresh, the pressure from the “new” water isn’t sufficient to fully “lift” the sagging pipe. But when it is plunged, the force clears the pipe completely, and the gradient is then sufficient until the shower is stopped, and the cycle repeats itself?

 

[kbdiy]

Because the 'plunge' starts a self-syphoning process that draws the water out. When all the water has drained the syphon effect stops until you repeat the process all over again, hence his assumption of sagging waste pipe.

 

[MasterMark]

Understood, thanks.

So to my previous point – if I’m having issues with both sink and shower (that exit the bathroom via different routes), the odds are that the sagging pipe would be on the outside of the building, rather than inside? Which would be a major bonus….. I’ll try and take some pics tonight or tomorrow morning when there’s light.

 

[MasterMark]

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• MasterMark
• 25 Nov 2013
• 1

Untitled

• MasterMark
• 25 Nov 2013
• 1

Untitled

• MasterMark
• 25 Nov 2013
• 1

Ok, so took some photos. One is of the pipework beneath the sink.

The second is the waste pipe from the toilet. The shower is out of picture to the left of the toilet, but presumably the drainage pipe from the shower joins this main waste pipe, as on the third photo from the outside, there's only one waste pipe exiting.

So the 3rd photo - you can see the waste pipe from the toilet on the right hand side, running from right to left. The pipe from the toilet is on the left hand side - there's a pipe, furthest left, running from just under the window frame. Not that one. The next pipe on the right is from the sink.

So for the shower, I'm guessing it's most likely the problem is going to be beneath the shower itself? But not sure what the problem with the sink is, unless the pipework underneath the sink has been done incorrectly?

 

[MasterMark]

Update – I kept the shower running after having plunged it so it drained smoothly, and tried the sink at the same time. It still didn’t drain properly, so I’m assuming the two issues are unrelated. I’ll have to get someone in to take up the shower/tiles to access the waste pipe, but does anyone have any thoughts re the sink? Does the pipework per the photo look correct?

Thanks again to everyone for the help!

 

[kbdiy]

So the basin waste is the one at a steep angle joining into the main stack at the branch? Can't see any reason there why it wouldn't drain properly so would assume the problem to be inside.

Are you sure it isn't clogged with soap scum, perhaps in the pipe after the trap as it passes through the wall? Could it be the same issue for the shower waste too?

Presumably the toilet flows ok and doesn't back up into the bowl when you flush it?

 

[MasterMark]

Thanks kbdiy. To answer your questions:

1) Yes, the toilet flushes fine.

2) Yes, the basin pipe is the small one going down at about 45 degrees from left to right, joining the main stack towards the bottom of the photo.

3) I think I may have already used a drain snake both in the shower and through the basin without coming across anything. But I’d have thought that if that was the problem, the plunging would have been enough to dislodge whatever was there anyway? And the fact that the shower drains after plunging, and the sink drains after compressing and then releasing the basin spring plug? But I could certainly try snaking again.

 

[kbdiy]

If it was me, I would put a hosepipe down each of the wastes and blast with mains pressure for a few minutes to see what happens. Soap scum might not be affected by a drain snake whereas a good blast of water might shift it - assuming there is something to shift of course!

 

[MasterMark]

understood, will give it a bash!