On Sun, 4 Apr 2004 15:33:35 +0100, "Jonathan Pearson"
As others have noted the fall can be as low as 18mm / metre run,
which is only just noticeable with the eye, the idea behind
relatively the low gradients is that if the pipe is too steep the
water can flow quicker than the turds, hence leaving them high and
dry in the pipe.

Absolutely, and as updated by the 2002 edition of the regs. Not as my
earlier outdated suggestion. (damm regs bible is getting old)

Sounds like the external branch and new plastic stack will go in without
hassle. My neighbours replacement black stack clicks like crazy everytime
the sun passes behind clouds, so I might suggest grey pipe instead.

Andy Hall wrote:
Perhaps there's a British Standard turd?

There is, although it's been europeanised now. Annex F of BS EN 997. They
also seem to believe sawdust is regularly expelled from pans.

--
Toby.

'One day son, all this will be finished'