On 5 Mar, 19:08, Hugo Nebula abuse@localhost wrote:
On Wed, 5 Mar 2008 01:08:50 -0800 (PST), a particular chimpanzee,
robgraham randomly hit the keyboard and
produced:

What the guy seemed to be suggesting is that I could get an inspection
chamber that I just sat on top of a bit of new concrete surrounding
the existing bend, and then flaunching it in. Going the brick route
is more work than replacing the bend with a plastic junction and
putting in a rodding eye :)

A properly constructed in-situ chamber needs to have a concrete base,
with a half-channel bedded on concrete and benched up. The sides of
the chamber are then two courses of brick, with the pipe having rocker
sections either side.

The alternative is a prefabricated chamber (which has the channels and
benching in the base, and collars at the exit of the chamber).

What your guy seems to be suggesting is the worst of both solutions;
slapping a bit of mortar around an open channel with plastic rings
above. Chances are the pipe will move relative to the 'benching',
allowing the sewage an easy place to leak into the ground or tree
roots to get in.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"

Did some investigation today and decided that my first choice is
financially and technically better even if there's more digging to
do. A reasonable size plastic inspection chamber and cover are
approaching £100. Going the rodding eye route will be a bit more
involved in replacing the offending SG bend with a plastic junction
etc but it avoids this benching etc and will I suspect be easier to
rod if required in future.

Thanks for your comments, guys

Rob