Green roof terrace - that's how it's done right

So that the roof terrace actually becomes a "green oasis", greening is required. What is needed, and how such a greening is properly built, you will learn in detail in this post.

Intensive greening

If a roof is also to be used as a roof terrace at the same time, a so-called intensive greening is more the means of choice. The other possible greening method, the extensive greening, is usually used only for unused roofs. Greening is then only with succulents and mosses on a substrate layer.

For an intensive greening, however, "real" floor structures are used, as they occur in nature. A simple substrate layer is not enough here.

Requirements for a greening

To be able to carry out such a greening, some conditions must be taken into account. Most important is a sufficient load capacity of the roof. Green roof areas sometimes create very high surface loads, which the roof must be able to cope with. A static assessment is mandatory here.

The design of the roof (warm roof or cold roof) also plays an important role in planning. Also on drainage and roof closure must be paid attention to the roof structure. In most cases, an intensive greening is only on one warm roof to be possible.

Roof loads and construction height

For intensive green roofs, an additional load for the roof in the range of more than 3 kN / m² is created. This corresponds to a weight of over 300 kg / m². A roof must be able to bear this additional burden.

In addition, in heavy rain, the soil absorbs the rainwater like a sponge and, therefore, during heavy rainfall, even significantly higher weight loads can occur in the short term due to the additional weight of the water.

Protection of the roof waterproofing

The roof seal must be sufficiently protected in any case. This happens through three different layers:

  • a separation layer (prevents chemical reactions between root layer and roof seal)
  • a root protection (sturdy plastic sheets or PUR coating, other coatings possible, prevent rooting)
  • an additional protective layer (mostly made of fleece, prevents the mechanical damage of the roof skin)

The so-called vegetation layer with the planned soil structure is then created above these layers.

Funding for green roofs

Green roofs are eligible for different levels of funding. The funding depends on the respective location and the federal state. In some federal states, up to 50% of the costs for intensive green roofs are promoted.

The construction height is around 25 cm - with a corresponding height of the roof garden must therefore be expected.

Tips & Tricks

Be sure to have your roof garden planned by a specialist. The basis for a planning should always be the FLL (Research Society for Landscape Development and Landscaping e.V.), which is the standard work for all types of green roofs.

Video Board: Building a Shed with a Green Roof: The Outer Shell