A green flat roof

In Germany there are numerous flat roofs. Many of them have significant problems in terms of their tightness. A good way to improve the seal, and at the same time to get even more benefits, is a green flat roof. However, there are clear differences between different greening approaches. The flat roof construction also plays a role. Below you will find information on what a green flat roof can look like.

The problem with flat roofs

In the 1970s, there was an unprecedented trend for the construction of flat roofs. In fact, many of these existing flat roofs would still be tight today, but most flat roofs do not get enough maintenance and care. Improved materials for flat roof sealing also provide only limited relief.

Remedy against short life of the seal - a green flat roof

One of the most important factors is the fact that the roof waterproofing is always exposed to the weather and therefore relatively short-lived. As a result, even with new flat roof constructions, this leads to a massive maintenance and care effort. However, it can be observed that a green flat roof counteracts this.

A green flat roof brings numerous advantages

Among other things, the life of the underlying flat roof seal is significantly extended. This is particularly interesting because a green flat roof brings many more benefits.

  • The roof seal is spared and the service life extended
  • thermal insulation
  • soundproofing
  • Creating a pleasant microclimate
  • Reduction of heat radiation
  • Reduction of the absorption of short-wave sunbeams (heat)
  • Effect like a drainage system with water storage
  • Creation of additional living space with a high recreational value

The importance of the green flat roof will continue to increase

The benefits of a green roof are indeed overwhelming. The very advantages that only affect the structural conditions speak for themselves. However, if one observes the trend, which clearly goes to living in the big city, green roofs are of much greater value.

Benefits for you and your environment

With a green flat roof you create an oasis of peace and relaxation. In addition, they make a valuable contribution to positively influencing the climate in the city. Measurements have shown that the heat in the city compared to the country, which can be up to 10 degrees in some cases, thus significantly reduced.

The disadvantages are partially neutralized by subsidies

For this reason, the greening of a flat roof also involves numerous subsidies from the state, municipalities and federal states. This is a not to be underestimated aspect, because a green roof also brings with it a lot of disadvantages.

  • costly in the application of a green roof
  • depending on the extent of greening more or less care intensive
  • Statics calculations by a recognized expert
  • Creation of an approved construction plan
  • building permits

Requirements for the roof construction before and during the greening

As you may already deduce, these are all economic disadvantages. The advantages that green roofs bring with them are clearly outweighed. However, there are also requirements for the roof construction. Thus, a warm roof is generally better suited for green roofs than a cold roof. The cold roof is ventilated, so it has an air layer in the layer structure. That's a static weak point.

greening variants

Here we come already to the differences of the different green roofs. Depending on the different load capacity of flat roofs, there are also different approaches for a green flat roof

  • extensive Green
  • intensive Green

A green flat roof in the form of an extensive greening

Extensive green roofing begins at a substrate height of 5 cm, making it suitable for mosses, lichens and sedum plants. Overall, the height of the substrate can be up to 15 cm and it is still an extensive greening. Possible plants are mosses, lichens, herbs, half-tall plants like grasses.

The intensive greening

In contrast, intensive greening starts at around 15 cm. Up to a layer height of the substrate of 25 cm one speaks of a simple intensive greening. This allows shrubs, bushes and woods. Above (from 25 cm substrate layering) it is an intensive greening on which also trees can grow. With the layer increase costs rise as well as care needs of green roofs.

Tips & Tricks

You should first go to the building office responsible for you. There you can tell if you receive funding. In addition, statements can be made about the approval procedure.

Under no circumstances may green roofs be managed by a specialist without static calculations. In addition, a flat roof expert should inspect the roof and check its suitability.

Depending on the condition of the flat roof, it is advisable to completely renovate the roof waterproofing immediately before the green roof. Of course, we also provide you with contributions in the house journal for [sealing a flat roof].

Video Board: DIY living green roof installation