Roland Perry wrote:

In message , at 08:19:24 on Thu, 30 Apr 2020,
Roland Perry remarked:
House has old lead pipe water main. This needs extending (with polypipe)
to new position within kitchen extension.

Plumber says this is difficult if the old pipe isn't circular enough to
attach the connector he has in mind.

Isn't there a connector which could be soldered to the lead pipe side,
somewhat irrespective of its exact profile?

[My preference is to polypipe all the way to the water meter in the
pavement, but that involves digging up (and reinstating) rather a lot of
concrete path. As well as presumably getting the Water Company
involved.]

ps The water company previously tested the potable supply for lead, and
declared it so low it probably wasn't a lead pipe anyway. Ho Hum.

I value all the comments made so far. Here's a photo (now I've started
to take apart the kitchen unit with the old stopcock in it).

http://www.perry.co.uk/images/stopcock.jpg

Points to note:

When buying the house the only visibility of the pipe was above the
unit's chipboard floor, about 1cm, which everyone declared to be black
polypipe (despite my misgivings).

There's a lead-to-copper connector whose body is almost spherical.

Above that is a copper reducer before the stopcock itself.

The floor is concrete and Marley tiles, and the stopcock needs moving
about two feet towards the camera, with the floor in the area below the
stopcock eventually being in the open air and level.

My solution so far has been to install a polypipe from roughly where the
camera is, to outside where the lead pipe starts heading for the street.

Didn't want to be doing any of this, but as the contractors have fled
because of lockdown, I would like to get them up to speed as quickly as
possible when they do eventually return.

How are you planning to bury the MDPE under the floor so that it is at
least 2' deep where it passes through the wall? Doesn't this involve
digging up the kitchen floor? Is there no way you can extend copper in
place of the existing stopcock and box it in? If you are going to be
digging up the floor and a 2' hole outside I'd strongly recommend
replacing the whole of the lead pipe to the stopcock. If by any chance
you've got retricted flow it may help this, as well as avoid the worry
of a buried adaptor with two compression joints.
--

Roger Hayter