Construction of flat roofs is one of the modern building concepts of our time. The best proof of this is the millions of square meters of flat roof area that have lasted for decades without damage. Besides gravel covered / open air weathering flat roofs, garden roofs are gaining in importance as the planted area is a partial compensation for sealing and thus can have a positive impact on town climate. Damage, resulting from a variety of causes like improper laying and material deficiencies or that which is caused by construction physics, chemistry or technology, have time and again led to heated and less than objective discussions about the safety and efficiency of flat roofs. By providing comprehensive information about Lucobit® sealing sheets we want to make a contribution to a more rational view.