Phenolic insulation boards are the most effective type of rigid insulation boards currently available. The phenolic insulation board is manufactured by a process in which a plastic foam forms an insulating core between two flexible facing layers. It has a high closed cell content and fine cell structure. Rigid phenolic insulation is produced by mixing high solids and phenolic resin with a surface acting agent. The heat created by the reaction evaporates a volatile liquid blowing agent in the mixture produces a mass of small bubbles in the material. The foam is then cured and manufactured in a continuous process to create thin sheet material which is laminated with various facings and cut into boards. Phenolic boards are laminated with pure aluminum foil facings, glass tissue facings, plasterboard.