On 08/06/2011 13:28, Robin wrote:
No idea how
the original 4" of fibreglass was installed unless child labour was
employed.

And why not? Or get a thin bird in! If you can get 8x1 Celotex in then
you can get a body in.

But would I get her out again?

I've put insulation between and over the joists in the loft of our "back
extension" by crawling around it: 375mm x 500mm hatch and a maximum
height between joists and rafters a good deal less than you have. It
helps though if you can put down something slippery to slide along (eg
old melamine boards) rather than the usual, rough boards. It may also
help to have done a bit of caving in one's youth

I'm very old and very tall, so I don't think so

I'm thinking of maybe pushing an 8x1 chipboard sheet across the joists
via the limited loft access and hoping that a second sheet would shunt
the first one to the back. It should then be relatively easy to slide
celotex over the chipboard surface. A bit of a dog's dinner but it's
the only way I can see it getting done.

Won't you have problems with air getting under the chipboard and/or
between the chipboard and the Celotex?


Is air a problem? I thought the whole idea of insulation was to trap
air. You probably didn't mean that though.
A long length of mdf skirting might be a good start if I can get it up
in the loft. Then I could maybe slide end-jointed lengths of celotex
along it on edge.