In administrative, industrial, and commercial buildings, flat roofs usually form the upper end of the building. However, this type of roof is now also often found in single and multi-storey residential buildings.
The structure of the flat roof consists of several functional layers. First of all, the said structure includes the vapour barrier, the thermal insulation, and the sealing. Depending on the type of use of the flat roof, you can add root protection, separating and drainage layers, protective and drainage sheets, heavy surface protection in the form of gravel or paving, as well as substrate and vegetation layers. All these layers must be sensibly coordinated with one another in the flat roof structure. In particular, the seal is heavily stressed by weather and environmental influences. This is why it needs a particular protection.
Above all, however, proper drainage plays an important role when it comes to flat roofs. Since unlike on a pitched roof, rainwater can accumulate on flat roofs without efficient drainage. However, the standing water increases the risk of leaks. In addition, the organic substances - such as leaves - deposited in there may lead to long-term damage to the roof waterproofing.
These are problems for which we at the company DÖRKEN offer you safe, efficient, and economical solutions with our expertise in the field of protective and drainage membranes.
Unused flat roof areas are not intended for the permanent residence of people or for use by vehicles. Such areas are usually filled with gravel and are usually only used for maintenance and repair work. For the protection of the waterproofing, a stable protective layer will be required between the top layer and the waterproofing. This should also ensure safe water drainage above the sealing level and consequently reliably prevent the gravel from soiling or silting up.
Large flat roof and ceiling areas of buildings and underground garages offer the ideal conditions for being used as traffic routes, play and leisure areas or as additional parking space. However, any precipitation and, if needed, facade water must not only be safely drained off on the surface and in the sealing layer. In fact, an efficient surface drainage is also required within the structural design of the said areas. Otherwise standing water may result in a destabilization of the substructure of traffic areas, by attack the pavement or causing frost damage.
On many flat roofs, attractive green spaces may be created as well. However, these place additional demands when it comes to the structure of the roof.
The conventional mineral drainage from gravel or chippings may only meet these requirements with great effort. In addition to the silting or soothing risk which may result in a gradual reduction in the drainage capacity, the required minimum thickness of such a structure already represents an obstacle when it comes to planning. In addition, the higher load is reflected in the construction costs due to the larger dimensioning of the load-bearing components.
The products DELTA®-TERRAXX and DELTA®-TERRAXX ULTRA can be laid as a horizontal drainage layer under useful areas on flat roofs and ceiling surfaces. For this purpose, the two-layer sandwich membrane offers a particularly high drainage capacity with an installation height of just a few centimetres, which - with a low static load - is noticeably higher than that of a classic gravel or of a gravel bed.