Blocked sink dilemma

[Tomw84]

A week ago my lodger told me the bathroom sink was draining slowly. I put some caustic soda down it and rinsed with a kettle. It made a few glugs, spat out some dirt and now it's completely blocked - no drainage at all. I tried using a snake, but it seems to be a build-up of dirt rather than anything the snake can grab onto, so that didn't work either.

I've had a plumber over and they tried a plunger and a hoover, but neither worked - apparently the sink is vented and the vents are right up against the wall, so they couldn't make a proper vacuum. They didn't want to use pressure machinery because it's a very old lead pipe and apparently that might burst it. I've been quoted almost £5k to have the pipe removed and replaced.

Before I consider that, is there any reason why I can't/shouldn't just saw off a section of the pipe below the u-bend, use some kind of big poking device to try and clear the blockage, then replace the missing section with a £10 plastic pipe?

Photos of:

1. Where the pipe connects to the basin
2. The U-bend
3. The bit of pipe I'd cut through
4. The pipe on the other side of the bath panel

 

[HERTS P&D]

Post some pictures.

Andy

 

[Tomw84]

Post some pictures.

Andy

Cheers - I've done that

 

[Harry Bloomfield]

I've been quoted almost £5k to have the pipe removed and replaced.

On the face of it - that price is ridiculous, for the work involved. Does the bath drain OK?

 

[Tomw84]

On the face of it - that price is ridiculous, for the work involved.

I'm on the second floor, so apparently scaffolding is needed

 

[CountryFan]

Caustic soda has probably solidified. Hard to tell if it's all lead, so could prove difficult getting a correct fitting. Is any part of the bath or basin waste copper or even pvc?

 

[HERTS P&D]

Remove the bath panel end, cut the lead and reaplce with a new trap and plastic pipe upto the lead and recoonect under the bath.

You will find that the blockage will be in the lead pipe from the basin. If not then come back to us.

Andy

 

[Harry Bloomfield]

I'm on the second floor, so apparently scaffolding is needed

So, £1,000 for scaff., what is costing the other £4,000?

 

[Tomw84]

So, £1,000 for scaff., what is costing the other £4,000?

£1.2k for scaffolding, £2.4k for labour and a bit more for materials + VAT on top

Re. what you you asked earlier, yeah, the bath is draining fine.

 

[Scally-Ho]

With modern DIY (bodgery) type fittings, it is fairly east to join modern plastic pipe to old lead waste, but be careful because if the old lead is in any way crystalline, then it would not be too difficult to fracture the lead. Now that said, McAlpine produce a universal type of coupling that could get you out of trouble for very little outlay. If the weight banding is visible on the lead, then a good curved shave hook with soon remove that to produce a reasonable smooth external pipe wall for the coupling rubbers/cones to grip upon. Your plumber should be ashamed of him/herself if they had not offered the quick workaround that would have seen the job completed and a satisfied customer with very little risk in the right hands.

https://www.screwfix.com/p/mcalpine-t28l-iso-compression-connection-straight-connector-white-40mm-x-38mm/564hr

 

[Harry Bloomfield]

Re. what you you asked earlier, yeah, the bath is draining fine.

I had in mind - that likely the washbasin and bath, both join together at some point, before exiting through the wall. If that is the case, then your washbasin drain is blocked inside the building, so no need for scaff., or all of that expense. A simple, cheap fix.

 

[Hugh Jaleak]

Can you see the pipework where it exits the wall outside? If the two pipes common into one internally and the bath is ok, then the problem is certainly internal, and a lot easier to sort out. Should be able to join onto the Lead with a Compression Waste joint, then run back to the basin in plastic.


Be careful though there isn't any traces of the Caustic Soda kicking around in the pipework, that stuff bites and doesn't ask any questions. They're left to the Hospital when they're working out what's caused the burns.

 

[Tomw84]

Can you see the pipework where it exits the wall outside? If the two pipes common into one internally and the bath is ok, then the problem is certainly internal, and a lot easier to sort out. Should be able to join onto the Lead with a Compression Waste joint, then run back to the basin in plastic.


Be careful though there isn't any traces of the Caustic Soda kicking around in the pipework, that stuff bites and doesn't ask any questions. They're left to the Hospital when they're working out what's caused the burns.

Annoyingly not - they feed into the main downpipe separately. But even if the blockage is in the external part of the pipe, it looks like it should be fairly easy for someone to unscrew/remove that section and clean it out, rather than replacing the whole waste pipe.

I'll have a crack at replacing the trap tomorrow and see if that works - with my PPE on!

 

[fixitflav]

Be careful though there isn't any traces of the Caustic Soda kicking around in the pipework, that stuff bites and doesn't ask any questions.

Not only that, but caustic soda dissolves lead, giving off hydrogen

 

[Harry Bloomfield]

Annoyingly not - they feed into the main downpipe separately. But even if the blockage is in the external part of the pipe, it looks like it should be fairly easy for someone to unscrew/remove that section and clean it out, rather than replacing the whole waste pipe.

I'll bet, it's the upper pipe, the one which rises up as it comes out through the wall, before T'ing into the main pipe.