Isover Spacesaver Loft Roll is a low density glass mineral roll supplied in 100mm to 200mm thicknesses. The strong, resilient and flexible rolls are pre-perforated to 2/580mm or 3/386mm widths to fit between most common joist spacings. Isover glass mineral wool insulation has an A1 Euroclass fire rating and is manufactured from up to 86% of recycled post-consumer glass that would otherwise go to landfill.