At present, flat roofs and underground garages are not only greened but planned for comprehensive utility. To save valuable and high priced land, not only terraces but also sporting facilities, playgrounds or roof cafés are installed.
Other examples include: parking lots, with corresponding driveways; airfields for helicopters; and areas for fire brigades access. These different uses are not independent but are realized in combination with intensive vegetation and walkways.
Walkways and driveways on buildings not only require enough load bearing capacity from the roof but also from system build-ups. These build-ups provide long term reliable functions, such as, drainage, thermal insulation, noise reduction and protection of the waterproofing. The entire use of the roof requires detailed solutions, for example, transition areas, supply facilities and drainage outlets, to ensure lasting functionality.
When designing a system build-up it is important to first address what kind of roof construction is to be used and what load it can bear. In addition, the thermal insulation boards need to be pressure resistant and carry the load of the system build-up. The applied loads vary from a single person with approx. 100 kg up to a lorry with a total load of 40 tons. On driveways, additional forces such as shear forces and torsional moments occur from steering, braking and accelerating. The waterproofing needs to be protected from these horizontal forces by installing additional slip sheets. The absorption of the forces is carried out by the roof's adjacent building parts or reinforced concrete kerb edgings.
The applied system build-ups require a high quality protection layer as well as a drainage layer that allow water to be drained off and protect the build-up from frost damage. A filter sheet prevents fine particles from being washed out of the base layer or out of the bedding material and any fine particles coming from the surface layer. Depending on the system weight, a load distributing base layer of gravel, concrete or comparable materials need to be installed. It is possible to use various materials for the surface layer, for example, concrete slabs, natural stones, elastic material, wood or asphalt.