On Dec 10, 2:42 pm, wrote:
On 28 Nov 2008 23:51:20 GMT, (Andrew



Gabriel) wrote:
In article ,
"Francis Kirby" writes:
Attic insulation, 30 cm rafter spacing. What would be best way to insulate
with this narrow spacing. Could I use spce blanket streatched over rafters?

I would get a roll of 100mm insulation (used for topping up),
and cut it into several 30cm wide rolls. (This is quite easy
with a long kitchen knife -- do it with the roll wrapping
still on.) Some rolls come sort of pre-perforated for cutting
to certain joist separations. If there's a 30cm pre-perforated
one, go for that. Otherwise try to get one which isn't pre-
perforated.

Having laid this between the joists, then lay another 100mm layer
(or more if you want) uncut full width across the top at right
angles.

The space blanket stuff has been discredited.

Thanks for the info. I've changed my news server, hence the delay in
responding.

I was going to do the roof rafters rather than the floor joists so to
speak. How do I keep the insulation in place?

That probably makes the solid board (Kingspan, Celotex) a more
attractive option. Cut to a friction fit, and just push between the
rafters.