Just thought I'd share this info with everyone. I've just added a Dormer to a new upstairs room. Basically 4" x 2" (95mm x 45mm) stud walls. I've 'stuffed' it with the following insulation called Rocksilk by Knauf. The spec. sheet gives the following details...
UNIVERSAL SLAB RS45 Thickness 100mm (I have also used 75mm) Length: 1200mm Width: 600mm Area per pack (m^2): 3.6 Lamda (W/mK): 0.035 R Value (m^2K/W): 2.85 Fire ClassSlabs per Pack: A1 Pack per Pallet: 5 Product Code: 2361392
The price for one pack from Sheffield Insulations in Aberdeen was =A332. So that's nearly =A310 per square metre. Quite expensive for what it is. It is good to work with, easily cut with a breadknife. Just cut it about a quarter inch oversize and push between the studs.
Chris.