Coating is

ANDULINA slate is made of bitumen and cellulose fibers. This bitumen slate, which is most often called “ondulin” (by the name of the manufacturer), is used in the same way as ordinary wavy sheets. They cost more than the usual coating, however, as practice shows, their durability is significantly inferior to their asbestos -cement "brothers". Their main advantage over the gray coating is a significantly lighter weight. There are also several analogues of Ondulin — Nulin, Gutta, Ondalyux and some others.