Leaking joint in drainage pipe - What do I need to buy?

[dominoman]

I've got a leak in a drainage pipe where it joins the main vertical soil pipe.

The leak comes whenever the sink or bath is used, because the pipe that carries the waste water towards the soil pipe has come loose. It has a soft rubber insert. I've tried to push it into the other pipe but after a day it came out again. I think it is too perished.

What part do i need to buy?

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• dominoman
• 25 May 2015
• 1

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• dominoman
• 25 May 2015
• 1

The other issue is that there is actually no slope at all on that drainage pipe. I guess moving that down is a bigger job as it means a new vertical soil pipe section?

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• dominoman
• 25 May 2015
• 1

 

[^woody^]

It's a strap on boss. Looks like 50mm, but measure the waste pipe.

There doesn't need to be a fall on that section of pipe.

 

[dominoman]

OK. Great. Thanks

With that information and knowing now that it is called a strap on boss I was able to Google it and found what I think I need...

http://www.nationalplastics.co.uk/i...sh-fit-110mm-ring-seal-soil-system-black.html

 

[dominoman]

So... I went to my local plumber's merchant with the rubber boss insert to have it replaced.

He told me that boss joint was intended for cast iron pipes and that there was no point putting a new rubber insert on as it wouldn't fit tight.

My pipes are all plastic. Is there a different joint I can use? How would I then fit it? I've never done any guttering or drainage work before but would like to try it myself if the process isnt too tricky to get right?

Close up picture below:

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• dominoman
• 8 Jun 2015
• 1

 

[noseall]

The whole lot, i.e. all the small bore stuff, looks like a bodge to me. It couldn't have been done by a plumber, surely?

 

[Agile]

I am surprised the merchant guy did not just show you the correct part to use for plastic pipe.

They usually try to be helpful although sometimes their knowledge is a bit lacking.

Tony

 

[dominoman]

Yes - the merchant's are usually really helpful. But this one wasn't. Probably it didn't help that I showed up 5 minutes before closing time...

Really what I'd like to do is fit a new rubber gasket anyway. Even though he told me you shouldnt on PVC, I've seen other fittings online that do use it for PVC.

I can see it was probably a bodge originally (as most things in this house we bought are), but if I can make it watertight for the time being that is good enough. We are doing more work on the house in a year or two so will likely replace those pipes anyway at that point.

The waste pipe diameter is 56mm. I've searched everywhere but can't find a boss that fits 110mm waste to a 56mm branch. Is there any other way I could seal it in without having to fit a whole new branch connector thing?

 

[JimCrow]

http://www.drainagecentral.co.uk/50...bthHqEhM7trad9bqP8zAqEj6Be6ImHdWtKhoCFv_w_wcB

 

[dominoman]

http://www.drainagecentral.co.uk/50...bthHqEhM7trad9bqP8zAqEj6Be6ImHdWtKhoCFv_w_wcB

Thanks. That looks like the right one, but my waste pipe measures 56mm. That one says 50mm. I have struggled to find a 56mm one anywhere.

 

[mogget]

The 50mm is a nominal size, for example I think the outside diameter of 32mm solvent weld waste pipe is actually 36mm, etc. Ive never actually bothered to measure though.

 

[Agile]

If you go into a merchant within 10 min of closing time dont expect much help! Sometimes OK if they know you and you have telephoned in advance to give them time to get it out.

That gasket should be OK. Most merchants will have them if you take a print out of that link to them.

Best to put the 50 mm in first then the outer part second. If it seems a little tight then a little washing up liquid helps to lubricate it.

Tony