Underground pvc to clay chamber advice please

[Fluffster]

Hi Guys

I need some advice please on underground drainage which I very rarely get invloved in.

I need to spec for a 100mm pvc soil pipe to connect into a 200mm clay sewer on a swept t junction with a inspection chamber

The depth of the clay pipe is approx 1200mm and is a combined waste sewer running along the back gardens of a row of about 10 houses built early 1900s we are in the middle of the run.

Is there a pre moulded chamber that will accept the 200mm pipe or will I have to build a formed concrete base with brick walled chamber.

Any advice would be most helpful.

Thank you.

Pete

[Hugh Jaleak]

I think preformed plastic bases are only made for 110 and 160mm dia. pipes. I would suggest (BCO allowing) your best bet would be to excavate and expose the existing 9" pipe, then carefully cut and remove the top half of a section to form a channel, and construct a masonry manhole around it.

BCO will advise on what they want to see, its also possible they may need you to remove a section of existing pipe and replace, thus providing an expansion joint in the existing run either side of proposed manhole.

9" pipe for 10 houses seems a bit excessive to me, but there may have been further intention to connect into it at the time it was laid. Be aware an excavation of that depth will require support too.

[Fluffster]

Cheers for that, I will speak to the approved inspector they are using for the job.
Much obliged

Pete