How to build garden roofs

The control of rainwater evacuation, optimal conditions for vegetation and the improved comfort of the building are essential requirements of a garden roof.

Preliminary analysis

The use of expanded clays allows us to respond to these needs in a simple and natural way, without overloading the structures.

The use of GECOL Arcilla expandida is possible in these types of applications at three different levels with different functions:

  • Light drainage layer:

Its high drainage power, combined with the capacity to store humidity in the internal porosity of the expanded clay grains, allows the application of light coats and variable thicknesses (small or high in accordance with project needs), capable at the same time of forming a useful reserve for the plants).

The mechanical resistance and stability of the expanded clay grains allow use thereof in bulk, even in the case of large thicknesses. In specific cases (vehicle exit zones, small constructions), it may also be applied onsite mixed with cement throughout the thickness to form porous concrete.

  • Culture substrate:

It may be used as a component of the culture substrate (with different grain sizes), providing physical and chemical advantages, in addition to the reduction of loads, as well as reducing the risk of substrate compaction.

It improves substrate durability, optimizing its chemical and physical characteristics, increasing water retention, thereby avoiding water-logging the soil to the benefit of the health of the plants.

  • Padding:

Reduction of loss moisture loss from evaporation and thermal shock (frost, etc.), applied as superficial substrate cover, also contributing its decorative function.

These types of solutions simultaneously provide high thermal resistance thanks to the insulating properties of expansive clay. In addition, it adapts to the different types of plants in accordance with the project or weather conditions.

Resistance to ice and fire must be added to all the aforementioned advantages, to the recyclable nature of the product, as it is fully mineral and adequate to ecological construction.

Technical considerations

When building roof gardens, various factors must be taken into account when preparing the substrate and subsequently applying the product:

  • The substrates must be clean, resistant and moist.
  • The joints described in the project must be respected.
  • Mix, pour and spread with a minimum thickness of 3 cm, leveling recoverable guide screeds.
  • Let dry for a minimum of 12 hours.

Recommended products

Light aggregate

Insulating aggregate

Warnings: The data provided by this Constructive Solution were prepared based on standard onsite installation processes. However, we recommend that you consult our Technical Department in the event of any specific circumstance