Composite roofing panel

A composite panel for roof insulation, said panel comprising a fibrous glass board susceptible to penetration of foamable liquid thereinto when foamable liquid is placed on an upper surface thereof, a generally uniformly perforated sheet on the upper surface of the board for limiting penetration of foamable liquid thereinto during manufacture of the panel while allowing bonding of foam thereto at the perforations, and a layer of plastic foam foamed and cured in place from foamable liquid placed on top of the perforated sheet, the perforated sheet having at least two generally circular holes per square inch, the diameter of the holes of the perforated sheet being 0.46 of an inch or less, and the amount of open area represented by the holes being less than 1.5 percent of the total area of the sheet.