Asbestos risk in my roof? What is this material?
My first thought was chip board but when looking closer the fine layers do apear similar to a product that was used in the U.S. during the war when there was a wood shortage. I would not mess with it. If it felt brittle like cement flakes it is probably A product that contains asbestos. If it is not disturbed there is no real risk. If you are planning on remodeling or repairing the old roof area have it tested first so you and your family are safe.