Replacing underground drainage clay with plastic – how do yo

[jazzbhatia]

I am in the process of building a rear extension. I have removed all the old underground clay pipework up to the manhole.

When connecting the new plastic pipe to the old clay channel/branch how is this done?

Can I simply sand the surface of the plastic pipe to achieve a course surface which the concrete will hold to (hopefully)

Thanks in advance

 

[garyo]

If you still have some of the clay branch you can use a PVC to clay adapter such as http://www.screwfix.com/p/flexible-adaptor/19914

 

[cotswoldbuilders]

You can get connectors, for connecting clay pipe to plastic.

 

[theoldun]

Not enough information to answer question.
No such animal as channel/branch in salt glazed
If you have one run into manhole then it will be straight channel, two runs into manhole will be either channel junction or straight channel with slipper.
Be it one or two runs, have you still got the collar on the fittings, or have you broke the collars, or have you cut the existing pipes back 100mm clear of manhole.
Regards oldun

 

[jazzbhatia]

Sorry all, theoldun is right I am not clear in what I am asking and guess my terminology is completely wrong.

I have attached some pictures which I hope makes it more clear. The half cut clay pipe (think it’s the channel) has been exposed as it was evident from excessive water in the trench that it has been leaking.

My plan is to remove the complete unit (which consists of two connections, one to soil stack and one to gully) and preferably replace with plastic.

My questions are:
1. Can you buy such a part in plastic? If so what is it called
2. If I have to replace with clay, how do I get a sound fit to the plastic pipe, will I need to make the surface course?
3. There is a vast amount of cement work that needs to be replaced; I propose to you 3:1 sharp sand and cement
4. I will possibly lay the new part (broken channel) and connect to the existing channel with neat cement, can you see any problems with using neat cement?
5. What is the best way to remove the cement from the channel to which my replacement part will connect to

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• jazzbhatia
• 3 Apr 2012
• 1

Untitled

• jazzbhatia
• 3 Apr 2012
• 1

Untitled

• jazzbhatia
• 3 Apr 2012
• 1

 

[cotswoldbuilders]

If theres not to much pipe work, why dont you replace the existing with a preformed plastic manhole, then renew the soil and gulley drains in plastic into new manhole.

 

[^woody^]

It looks like that collar is cracked, so you wont get a connection to it. The whole lot will have to be removed into the chamber and replaced

You may be able to leave the chamber channel in-situ though and just connect to that - if you are careful when breaking the other stuff out

 

[jazzbhatia]

Don't want to replace the manhole as its shared.

what cement mix do you recommend on the new channel and actual manhole itself

thanks

 

[^woody^]

Whether you want to or not, you can't just "cement" a connection as it will move and crack and then you have a much bigger problem

 

[jazzbhatia]

Hoe do you connect a plastic pipe to clay channel

 

[Hugh Jaleak]

If the pipe is intact, (just collar broken) you may get away with fitting a McAlpine DC-1 coupling into the clay socket, come away from that in 110mm plastic. If not i'd carefully remove the existing clay pipe into the manhole and fit a new piece of salt glazed pipe to get clear of the manhole, so it all lines up nicely without a 'lip' where solids can catch. You can then couple onto that with the plastic. Plastic has a smaller outside diameter than the clayware and will present a problem when trying to seal the hole left where the salt glazed has been removed.

Personally i'd use granolithic mortar to repair the benching. Use grano dust instead of sand in a strong mix, add just enough water to make it workable.

 

[theoldun]

What you have is a 900mm bottom channel consisting of a 300mm LH 45degree channel junction, joined to 600mm LH 45 degree channel junction and an approx 60 degree three quarter section bend (slipper) which has a lump broken of from it, but will still perform.
Assume the inlet with the orange bag stuffed in it is upstream and this is the section you dug out and wish to replace.
Question. Where does this inlet run to and what does it serve? Is this inlet the one with the cracked collar? Is the first connection with the white bag stuffed in it still used?
Answer questions, will tell you what to do.
oldun