Ondulin is a strong sheets that have a wavy shape. It is made of fiberglass or cellulose, which are first saturated with bitumen, and then painted in a variety of colors. Ondulin is easy, but at the same time reliable material that does not make noise during the rain. In addition, it is economical. How to calculate Ondulin on the roof, can be easily recognized on a special site. Here you can also see a video on its installation.