Polystyrene foam, Hydrofoam, and Roofing
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.
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Update: June 2012