Loft insulation £3 a roll any good?

[torqueofthedevil]

Just moved into a house with only 75mm loft insulation and it is cold! I can't believe u can get rolls of insulation for £3 from N-power. I will be able to put 270mm on for about £70!

Questions are:

Is this good stuff?
Is it mineral fibre rather than glass?
I will be getting someone to fit it - woul companies supply and fit their own insulation cheaper than if u got the npower stuff and got somebody in to fit?
I don't plan on using the loft as storage space so will happily cross lay the insulation across the joists - if I ever have to temporarily compress the insulation with boards to allow me to work on underside of the roof will it ruin the insulation?

Cheers

[torqueofthedevil]

I cconsidered doing it myself but for 150 can get it supplied and fitted. Seems worth it to get it done properly and without the itchiness!