Extensive green roof

»In extensive greening the following forms of cultivation can be defined:

  • moss and sedum planting
  • sedum-moss herbaceous planting
  • sedum-grasses-herbaceous planting
  • grasses-herbaceous planting.« (Source: FLL)

Depending on location and climate conditions, extensive green roofs are relatively lean and exert smaller loads on structural elements of a building. Due to cold winters and hot dry summers in southeastern parts of Europe, soil thickness below 8-10 cm should be avoided. Besides, the weight of this soil thickness provides the necessary protection from wind suction.  All above vegetation requires drainage and appropriate water storage capacity of at least 5 – 10 l/m2. Although a welcome improvement, watering is not necessary. If the roof is not easily accessible for maintenance, the vegetation is kept in good shape by installing a capillary watering system.

Systems

OPTIMO system

OPTIMO roofs are optimally layered flat roofs where instead of the heavy inclination concrete, the desired slope is achieved with FIBRANxps inclination thermal insulation boards.

The system was designed with the aim of reducing the flat roof load, as its slope is achieved with FIBRANxps INCLINE – special inclined boards of thermal insulation. Additionally, the thermally insulated inclination layer improves the assembly's total thermal resistance.

CLASSIC system

The conventional flat roof, where the desired slope is achieved using inclination concrete.

The advantage of the conventional flat roof system is that the waterproofing bitumen strips can be heat welded directly onto the concrete inclination layer. Its disadvantage, however, is the inclination layer's heavy load and higher thickness. As a rule, the inclination concrete must be at least 5 cm thick at the drain. In the more contemporary OPTIMO system, inclination thermal insulation boards are used instead of the heavy concrete.

PLUS system

An existing flat roof can be renovated by upgrading with the PLUS system. A thermal insulation layer is added. Optionally, or as needed, a new waterproofing layer is laid, or the inclination slope is corrected.

An existing flat roof with insufficient thermal insulation can be effectively upgraded and its energy efficiency enhanced with an additional layer of thermal insulation. After stripping the upper roof layers, thermal insulation boards are installed on the waterproofing layer and the inverted flat roof's two-levered roof drainage system is put in place. The final layer is a matter of choice and depends largely on our intended use of the roof's surface. However, this upgrade is only applicable if the waterproofing layer is intact. Otherwise, a roof renovation is required prior to upgrading its energy efficiency.