Abstract: A baffle board (10) is disclosed for being mounted between the roof and ceiling of a room to provide ventilation along the underside of the roof and to prevent insulation between the ceiling and roof from being disturbed by air currents. Baffle (10) includes a sheet of stiff, relatively thin material (11) having outwardly and longitudinally extending side tabs (12, 13) defined by respective, perforated lines (12a, 13a). Side tabs (12, 13) are adapted to be folded at substantially right angles to the sheet and fastened to the inner facing surfaces of adjacent roof rafters. Sheet (11) also defines on one end thereof an end tab (14) defined by score lines (14a, 14b, 14c). End tab (14) is adapted to be folded back under sheet (11) and fastened to the top plate of the exterior wall.