What mix(es) would suit re-rendering a chimney-breast in a loft
please?

It's a Victorian terrace with the original render loose. Smoke test
shows no leaks yet into the loft, but I've been told gas fitters may
still not fit/pass gas fires unless the render is in good nick.
And re-doing it will cut down on the dust in the loft.

The original stuff seems to be quite light compared with modern
sand/cement render or haunching; and its full of small bits of glass,
broken brick and other stuff; but its harder than the lime mortar
between the bricks. Photos
here if they are of any use.
http://s854.photobucket.com/albums/a...himney-render/
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com

Many thanks for all that.

I would also say it doesn't need to be there at all, providing
the pointing is in good condition, but I don't know if there
are specific regs for gas flues that would require it.
BG fitted a gas fire for me in 1986 in a victorian house
without any render on the chimney in the loft, but gas rules
have changed since then (most notably in 1988).

Probably my misunderstanding. I've checked with the relevant neighbour
and she says the fitter may have meant that if it's already rendered
then the render needs to be in good nick. That'd fit with your
suggestion it was rendered to fix past leaks.

BTW, don't go raking out any significant depth of pointing
from the chimney without first looking down the flues to see
how much is still left on the insides. Over the years, you
might find half of it has been washed away inside particularly
on the first vertical part down to the first bend, and if you
rake out the outside, there's nothing left holding up the pile
of bricks formerly known as the chimney.

Thank you again. I'd not have enjoyed that opportunity to learn from my
mistakes.

--
Robin
PM may be sent to rbw0{at}hotmail{dot}com