Simple Drainage Repair - just checking?

[michcosg]

Hi folks

I am about to repair a section of underground drainpipe. As a London plumber, where specialists are aplenty, drainage is something I confess I have very little experience of. I thought therefore I would at least check in with you folks to ensure I am not missing something basic or indeed need to refer it to a specialist. Please see photo attached.

Not very apparent from the photo is the fact the the hidden side of the collar of the clayware pipe has broken off. The clayware gully seems to be ok. This would seem to have occurred because the largely clay substrate has shifted to the right, skewing very slightly the clayware pipe to the gully. The section of clayware pipe feeds I think a main run about a metre behind.

The plan is to cut the clayware pipe a small way back with an angle grinder, insert a small section of underground pipe and attach it with two Fernco couplings? I appreciate a better solution might be to perhaps replace the whole branch to the main run using an appropriately offset section to accomodate the skew. However the skew is very slight maybe 3 cms and who is to say it wont skew back! I was going to leave the underlying substrate as is ie not underlay with 'granular' fill as my book (Mechanical Services Book 2 Blower) suggests in some cases ...presumably by that it means sand?

Comments or suggestions welcome.

 

[Irish]

Fern co coupling and new bottle gulley set it in a week mix of sharp sand and cement

 

[snowhead]

Agree new gulley is a must, it'll be cracked somewhere

 

[Ermintrude]

Looks like the salt glaze collar split ??? Cut it back fit an appropriate band seal and new trapped gully.

 

[lame plumber]

or youcan get the whole lot relined using epoxy mix and a balloon, that way no digging and sealed drains, the experts in this started doing it in London to save digging all the roads

 

[mike-c]

You will need to hire all these guys if you want the job done properly !!

 

[michcosg]

Thanks guys

Info update: skew is less than 1 cm.

We are at least agreed that the Fernco couplings are an adequate solution. I don't think there is any problem with the gully, but I will put some flourescent tracer dye down it by way of checking. Would prefer not to have to dig it out! Intend to post the completed job.

 

[michcosg]

Thanks Snowhead

 

[michcosg]

Thanks Irish.

 

[michcosg]

As promised please find an image of the completed job attached



It was a bit of a job getting in the two Fercos as unlike normal 'equal' slip couplings, these reducer type couplings would not slip back along the larger clayware drain pipe. However there was some leeway on account of the fanning out portion of each of these couplings, flexibility of the rubber couplings themselves and of course could cut the normal drain pipe a little shorter.

 

[michcosg]

PS Did also put some tracer dye down the gully to test but admit, heart was not in it - no apparent damage to the robust gully. So not block up open exit end properly...hence when came out a little later to check, dye all over place having come out this end. Lesson: put a proper stop end over exit end AND seal entryend from rain, if going to test like this!