What type of insulation?

[ianrb]

Going to do the roof insulation on a small extension, and it appears I have a choice between traditional glass fibre, natural wool or recycled plastic. Granted there may be other alternatives, but those 3 are what's on offer at my local B&Q. Are any better or worse than any other? I would prefer to avoid the glass fibre ones as I know from past experience that it is an irritant.

[roofer]

Whatever has the best U value for a given thickness.

[ianrb]

I appreciate that to some extent the insulation properties and thickness of insulation need to be considered, however I was more interested in how easy or difficult the various types of insulation are to install and if any of them had any particular problems, e.g. rodent resistance, fire resistance etc.

[TooLateForAName]

natural wool is nicest to deal with - but much more expensive.
the recycled plastic is a reasonable compromise - not as itchy/unpleasant as rockwool but still fairly cheap.

If you are not in a hurry wait a bit until npower/powergen next do their £1/roll offer.