I'm just looking at getting my roof redone. As we have attic rooms I want to put some insulation under the tiles (we need all the space we can get so I need something thin that'll go between the tiles and the roof).

Anyone had any experience of this kind of stuff? I know various different things have different problems, for instance foil loses effectiveness after a few years as the shiny surface flakes off, and foam loses effectiveness when it gets saturated....

Any ideas?