I used a bread knife for cutting it. Found it easier to handle.Ah that's good to know! I've already hacked 2 of the 400mm lengths down to size which wasn't fun with a stanley knife. I'll saw it down in the bag going forward. I've also got the added fun of having to remove the old blown insulation first by hand. Potentially odd question but did you find any random bits of slate on your lath & plaster ceiling? I'm wondering whether it was used an an old school form of insulation or sound proofing.