On 16/11/2020 21:54, Theo wrote:
Dave Liquorice wrote:
On Sun, 15 Nov 2020 23:03:41 +0000, alan_m wrote:

You can also get real wool insulation but more expensive ...

But very nice to handle and no irritating fibres or dust. It does
shed fibres though.

It seems prices are pretty constant across suppliers. According to my
calculations:

Mineral wool: £3/sqm (200mm thick)
Encapsulated mineral wool: £10/sqm (200mm thick)
Polyester: £14/sqm (200mm thick = 100mm@£7x2)
Sheep's wool: £13-18/sqm (150mm thick)

Be careful with sheeps wool. It is supposed to be treated
to kill any possible parasites, but there have been incidences
where people have used it, with good intentions inside walls
of super-insulated new builds and the treatment was either
not done, or ineffective.

Don't overlook PIR , 'Celotex'. Unless you have a lot
of aluminium or magnesium up there, a domestic fire won't
get up to the temperature where PIR actually burns.