radiant barrier foil; how good does it work? will it hurt my flat roof material.?

Answer 1

Radiant barrier foil works great when used in accordance with the manufacturer's instructions. Where on a flat roof are you proposing to use it - below the rubber membrane, or below the insulation, or even below the deck? Check the manufacturer's instructions, and also check with the manufacturer of the type of roof you have - Carlisle SynTec for rubber roofing, or VersiGard, or Mulehide to name a few. If it is a built-up asphalt roof, try GAF.