Rigid boards are plastic foams or fibrous materials
pressed or extruded into board-like forms. Common materials include
polystyrene, urethane or glass fiber. Polystyrene and urethane
have superior insulating qualities, and would therefore make them
a better choice than batts or blankets if it were not for their
flammability. When installed inside a house, the boards require
an additional covering of a minimum of 1/2 in.-thick fireproof
material such as gypsum wall board. Rigid board has the advantages
of structural strength, low weight and high R per inch. To achieve
an R-30 using glass fiber blankets would require roughly 8.5 in.
With rigid urethane boards, R-30 can be attained with only 5.5
in. Rigid boards come faced and unfaced. Some are faced with a
reflective material that acts as a vapor barrier and reduces heat
flow when facing a dead air space.
Rigid boards are plastic foams or fibrous materials
pressed or extruded into board-like forms. Common materials include
polystyrene, urethane or glass fiber. Polystyrene and urethane
have superior insulating qualities, and would therefore make them
a better choice than batts or blankets if it were not for their
flammability. When installed inside a house, the boards require
an additional covering of a minimum of 1/2 in.-thick fireproof
material such as gypsum wall board. Rigid board has the advantages
of structural strength, low weight and high R per inch. To achieve
an R-30 using glass fiber blankets would require roughly 8.5 in.
With rigid urethane boards, R-30 can be attained with only 5.5
in. Rigid boards come faced and unfaced. Some are faced with a
reflective material that acts as a vapor barrier and reduces heat
flow when facing a dead air space.
