WC Blockage

[Temp]

Could this be a case of the liquids going too fast and leaving the solids behind? I've heard that can happen if drains are too steep by not sure if its a myth? 

 

[Onoff]

3 hours ago, Temp said:

Could this be a case of the liquids going too fast and leaving the solids behind? I've heard that can happen if drains are too steep by not sure if its a myth? 

 

 

I'll measure the drain angles later. Will also try another synchronised flush with downstairs. 

[scottishjohn]

just get the attachmnet for the power wash and do it right

-you probably got stuff dryed onto inside of pipe making something the new stuff can catch on

angle has not been as much of a problem since plastic pipes as they are not pourous and much more slippery to start with # 

leave it flat and yes it will gather up .but a steeper angle not a problem 

[PeterW]

More likely that it is too shallow and it’s a convoluted route slowing it down. Why can’t it go directly across the ceiling ..?

[Onoff]

10 minutes ago, PeterW said:

More likely that it is too shallow and it’s a convoluted route slowing it down. Why can’t it go directly across the ceiling ..?

 

It did originally, but that got in the way of doing other new pipes etc.

[PeterW]

Looks like you have clearance - I would be re-routing that as it looks too shallow and the changes in direction will not be helping. 

[Onoff]

31 minutes ago, PeterW said:

Looks like you have clearance - I would be re-routing that as it looks too shallow and the changes in direction will not be helping. 

 

This was it originally:

 

 

[Jeremy Harris]

Bends slow flow down a lot, especially on runs with a fairly shallow fall, and when the flow is slow, especially where toilet paper hasn't yet had time to break up properly, there's a fair chance of getting a soft blockage. 

 

The recurring problem we had with our first house was because the foul drain had been re-routed when it was connected to mains drainage.  This meant that the toilet pipe discharged directly to a chamber about 1 1/2m away, just the other side of the (ground floor) bathroom wall, with a right angle bend in that chamber to a fairly shallow run across the back of the house to another chamber.  It was that run across the back that always blocked, never the run down the side of the house out to the main sewer, even though the latter was also at a shallow angle.

 

I think that part of the reason that sodium hydroxide works well to clear blockages like this is just that it dissolves everything, so making it all liquid.  I'm convinced that it's mainly toilet paper that causes the problem, by sticking to the sides of the pipe when the flow speed is low.

[Stewpot]

6 hours ago, Temp said:

Could this be a case of the liquids going too fast and leaving the solids behind? I've heard that can happen if drains are too steep by not sure if its a myth?

 

I've read that somewhere, and I nearly posted about it earlier, but then thought, in reality, it just didn't sound plausible.

 

It's certainly counter intuitive. But then I also read that a flush will travel down the pipe as a wave (presumable in a near horizontal pipe), which I suppose is different from a shove. If the phenomenon does exist, it may be exacerbated by modern low volume flushes.

[PeterW]

I would redo that and also get the flow from the basin and shower into the pipe as high up as possible too as otherwise it will just continue to block. 

[Cpd]

12 minutes ago, Stewpot said:

Could this be a case of the liquids going too fast and leaving the solids behind?

 

12 minutes ago, Stewpot said:

I've read that somewhere, and I nearly posted about it earlier, but then thought, in reality, it just didn't sound plausible.

pretty sure when I was researching about this that a steep fall is not a problem

[Jeremy Harris]

2 minutes ago, Cpd said:

 

pretty sure when I was researching about this that a steep fall is not a problem

 

 

Yes, building regs were revised a few years ago, so there's now no limit on the steepness of the fall, and no requirement to faff around using back drop chambers if the fall happens to be a bit steep.

[joe90]

4 minutes ago, Cpd said:

pretty sure when I was researching about this that a steep fall is not a problem

I agree, and with @PeterW above, too shallow a run. Why the two 90’ bends with spurs and blanks in?

[Temp]

Have I understood correctly.. The run goes vertical -> horizontal -> vertical outside stack?

 

You have a large radius bend as the bottom of the outside stack but not on the bottom of the first vertical section Indoors? Perhaps changing that to a large rad would help?

Edited January 13, 2020 by Temp

[Onoff]

1 hour ago, PeterW said:

I would redo that and also get the flow from the basin and shower into the pipe as high up as possible too as otherwise it will just continue to block. 

 

The shower isn't used now, like at all since we've had the downstairs one up and running. The basin in there is though regularly used. That white waste exits the soffit separately and doesn't connect to this stack. 

[Onoff]

33 minutes ago, Temp said:

Have I understood correctly.. The run goes vertical -> horizontal -> vertical outside stack?

 

You have a large radius bend as the bottom of the outside stack but not on the bottom of the first vertical section Indoors? Perhaps changing that to a large rad would help?

 

You mean a rest bend. Not the height to do so in the loft.

[PeterW]

7 minutes ago, Onoff said:

 

The shower isn't used now, like at all since we've had the downstairs one up and running. The basin in there is though regularly used. That white waste exits the soffit separately and doesn't connect to this stack. 

I would connect it to that stack as it will give you a decent clean flow following the WC usage ... 

[Mr Punter]

Can you get rid of the branch on top of the elbow, just have the elbow and lift the horizontal pipe so it all has a really nice fall to the outside?  You would probably gain 200mm in fall and therefore no issues.