App membrane is made up of bitumen. bitumen is a kind of waterproofing and road building substance that has been used in various forms. a waterproofing membrane is a thin layer of water-tight material that is put over a surface. this layer is extended and does not permit water to pass through it. we can use these membranes over terrace slabs and balconies, in concrete water tanks, in swimming pools, beneath and around basements and also over landscaped concrete decks. actually by adding other materials to the bitumen, companies can provide a longer-lasting, more durable product – giving it either plastic or rubber properties. modifying bitumen makes it qualified to resist a wide temperature range, and remarkable weather proofing.