FanFold by Plasti-Fab® is designed to provide a continuous insulating underlayment that will help to reduce air leakage that can create drafts that carry dust and dirt into the building envelope. FanFold by Plasti-Fab® consists of a Type 1, expanded polystyrene (EPS) insulation core material (R-value of 3.75 per inch) with a thin film laminated to both sides. The branded film includes horizontal & vertical gridlines spaced at 51 mm (2’’) on centre to assist with installation. FanFold is manufactured by Plasti-Fab® so that each piece folds into a stack that can be handled easily. On the jobsite Fanfold opens into a 1.22 m x 3.66 m (4 ft x 24 ft) section that covers a large area quickly. All of these features add up to make FanFold one of the most versatile products on the market today.