Rockwool’s Flexi SlabDelayed implementation of the new Part L to April 1 2006 enabled British Gypsum-Isover to further develop products, as marketing manager Gerry Mitchell explains: "We introduced Isowool Hi-Cav as a high performance full-fill solution for masonry cavity walls early in 2005 anticipating an early change to Part L, but the delay allowed us to further improve our production …