Abstract: Dimensionally stable alkenyl aromatic thermoplastic synthetic resinous elongate foam bodies having closed noninterconnecting gas-containing cells having an average cell size of 0.05 to 2.0 millimeters, a minimum cross-sectional dimension of at least 0.25 inch, a cross-sectional area of at least 8 square inches, a water vapor permeability not greater than 1.8 perm inch, a density of from 1.0 to 5.0 pounds per cubic foot (16 to 80 g/l), and an absolute dimensional stability of less than 4 percent in any direction when measured by the test designated ASTM D2126/C578 are prepared using 1,1-difluoro-1-chloroethane as a blowing agent and extruding at controlled temperatures.

Abstract: Alkenyl aromatic thermoplastic synthetic resinous elongate foam bodies having a machine direction, a traverse direction and closed noninterconnecting gas-containing cells are prepared using 1,1-difluoro-1-chloroethane as a blowing agent. These foam bodies have an average cell size of 0.05 to 2.0 millimeters, a minimum cross-sectional dimension of at least 0.25 inch, a cross-sectional area of at least 8 square inches, a water vapor permeability not greater than 1.8 perm inch, a density not exceeding 2.4 pounds per cubic foot, and an absolute dimensional stability of less than 4 percent in any direction when measured by the test designated ASTM D2126/C578. Also disclosed is a method for preparing such foam bodies, other alkenyl aromatic thermoplastic synthetic resinous elongate foam bodies having the same criteria, except a density from 2.4 to 5.0 pounds per cubic foot and a method for preparing such greater density foam bodies.

Abstract: In a roof wherein the roof has a water impermeable membrane disposed on a roof deck and a closed cell insulation material disposed over the membrane, individual blocks of insulating material are tied together by a water permeable sheet such as a scrim to permit floating of the insulation and a protective layer disposed thereon in the event of ponding.