The App Membrane, which stands for Atactic Polypropylene Membrane, is a form of waterproofing material made from bitumen. These membranes are basically available in rolls. With the use of good craftsmanship the APP membrane is a highly efficient and long lasting waterproofing material that is used in the majority of construction activities. On the top of all this, the App Membrane is a typical waterproofing material that is used on concrete flat roofs, which are still roofs and low-pitch roofs.