best insulation for roof

Just wondering what peoples experience is, in the best form of insulation for
(1) Insulation for 1st floor 9" joists with attic rooms above
(2) Pitched roof over attic space

Any comments would be most welcome

For the joists im nto sure if you need it. its not necessary to keep the heat down and there are other better ways of reducing noise transfer. But rigid sheets of rockwoll would do a decent job of the noise problem
On the pitched roof you can go with kingspan rigid board (various widths available) between the joists or the thin foiled insulation called Actis triso super 10 which can be stapled tot he joists. its only 25m thick and has the same qualities as 250mm of glasswool. Costs around 20/m2

thanks ludermor, think i'll still put insulation between the 1st floor joists, as even though i've attic rooms, they're not bedrooms and will only be used for storage and hopefully a "lads pad" if i'm allowed. Therefore I'd like to minimise heat transfer from ground floor to attic.

has anyone any experience of using this company http://www.uvalue.ie/ which can supply and fit the foil type insualtion ACTIS.
i am wanting to know if it can be used to dry line external walls in a house. it appears to only reference it for underfloor and attic which i presume it is best suited due to its thickness.

has anyone used it and does it give equivalent uvalues when compared to much thicker traditional insulation

I looked in to using one of the foil products for drylining. Mainly because of the claims re u value, small space needed and the ease of use (no dust etc). I was put off when I was was informed that it would need an air gap both sides on a battan system thereby negating the space saving advantage. And for some reason I felt that it may not be that good for "insulating in" the type of heat we generate in our homes. Anyway, I've ended up going for a product called Kingspan Kooltherm K17 and Kingspan Reveal Board (KRB). Delivery is due on Thursday. Hopefully it will be a success as the money is now spent.

Regards
Franm
ps it's for a renovation project.
pps I've no connection with any of these companies

Ive used a foil type on the inside of all exterior walls, its battened on, to which the slabs will be attatched. We followed the manufacturers advice and no mention of gap on wall side of foil. The foil is directly on the wall. We also have an insulation in the cavity. We are awaiting the skim finish to be applied. Its a dormer so we used fibre glass in the rafters and then placed the foil accross the rafters, battened up the rafters and slabbed them.