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Name: Cornelius
Status: Educator
Age: Old
Location: N/A
Country: N/A
Date: November 2002

I am a scientist, experienced in construction 50 years. Can ordinary Polystyrene foam be recycled into hydrofoam to spray on roofs as a substitute for tar and felt, as in usual gravel "built-up" roofs ? I understand little use has been found for used Polystyrene foam, so it has become a surplus unused commodity.

Florida weather is very hard on built-up roofs. Thanks.

Polystyrene foam can be depolymerized under anaerobic conditions to yield styrene monomer, so it is not really unusable; however, in certain geographic areas this conversion may not be economically feasible (yet). It is also recycled into Polystyrene foam packaging "worms". From the insulation point of view it should work O.K.; however, it would have to be cleaned up to remove other trash. Flammability would also be an issue for its use as a residential insulation. Polystyrene foam is very combustible and the vapors, gases, and particulates produced by burning are very toxic.

Vince Calder

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