Topband: Aluminium roof vs antenna performance

[Riccardo Negro]

Hi all,
tomorrow I must decide which type of insulating system to be used under the
tiles of my new roof. Roof's structure is classic wooden and total surface
is 220 square meters.
Since there will be several antennas for 80 / 160 sorrounding the house I
am wondering if using insulating panels (polystyrene) covered with a foil
of ALUMINIUM (to reflect heath) could become a nightmare for antenna
resonance, pattern, etc.
The point is: better to have or not to have a roof with aluminium under the
tiles ?
Many thanks for your kind advice !
73 de Rik, IK2CAW