Radiant barrier foil insulation in a flat roof

[GroundLoop]

Has anyone installed atticfoil or a similar product on the inside of a flat roof? I am debating if this would be benefical for a flat roof. See www.youtube.com/watch?v=CjwZXoRzRiM for installation in a cathedral ceiling.

 

[Desertwndrr]

For a flat roof I have always used a foam over the deck that had a radiant barrier on it. That way it is on top of the framing keeping as much heat off the wood as possible.