Roof as a green island

Island is among the countries where green roofs have been a common feature of local architecture for centuries, and in Hungary and Switzerland, they are used to attempt to restore original vegetation to certain areas. This type of building construction is currently becoming a phenomenon in our country as well.


As a result of gradual warming and the fact that people do not know how to effectively capture water from heavy rains, the landscape is drying out. However, a number of measures can be taken to adapt to climate change – one of them is to utilize the potential of so-called green roofs, which are roof structures partially or completely covered with soil and vegetation. This ensures their ability to capture rainwater and slow its runoff during heavy rains. There is also greater evaporation of moisture from the roof, cooling both the building and its immediate surroundings. Green roofs are thus an effective tool in preventing the creation of so-called urban heat islands. This is related to another advantage, namely a longer lifespan of the roof, respectively the insulation materials used. In the summer months, the temperature of a conventional roof structure can rise to as high as 70 degrees Celsius, leading to faster material wear. In contrast, the temperature of a green roof remains around 35 degrees, which guarantees it up to double the lifespan compared to a conventional roof.

Environmentally Friendly Retention-Vegetation Board

Green roofs – extensive, biodiverse, and semi-intensive – can be implemented using the retention-vegetation board AQUADESK, developed in cooperation with the Faculty of Civil Engineering at VUT Brno by the company RETEX, a.s. It is an innovative material for green roof assemblies, made from recycled PET bottle polyester fibers and crushed non-woven textiles, bonded together with fusible fibers, without the use of chemical additives. This material is also fully recyclable, has balanced retention and drainage parameters, and another advantage is its protection of waterproofing – both during the installation process of the green roof and throughout its maintenance.

Installation Can Be Managed by Laypeople

After being dampened with water, the board is not carried away by the wind, it does not need to be weighted down in any way, is not displaced during mechanical application of the substrate, can be easily divided, and does not require special qualifications from the implementation team. This assembly of the green roof can therefore be confidently used even when the house is built by oneself. Other criteria in the development of this material, alongside the already mentioned simple installation, included physical resistance to mechanical damage, high water retention capacity, the highest possible utility value (cost/performance ratio), and environmental friendliness. The company RETEX has over sixty-five years of experience in recycling textiles and producing materials from recyclables. Successfully achieving the development goals for the AQAUDESK material was made possible not only due to recycling experience but also thanks to material sources, its own technological waste, and waste from customers in the automotive industry.

A Step into the Future

The developed material was tested on the testing and educational facility EnviHUT in the research complex of the Brno University of Technology. More than 120 sensors were placed on the roof and walls of the facility, monitoring the building's physical behavior during demanding climatic conditions: during heavy precipitation, in gusty winds, or long periods of drought.

The material AQUADESK allows the roots of the roof vegetation to grow into its structure, which leads to the strengthening of the layer system. This results in lower substrate consumption and a subsequent reduction in the weight of the entire layer system. Thanks to all its advantages, this material could soon become part of the preferred solutions for green roofs.

Board dimensions [mm]	1200 × 600
Material composition	recycled polyester
Surface mass [g/m²]	2000	3000	4000	± 15 %
Thickness [mm]	20	30	40	± 15 %
Maximum water capacity [l/m²]	12	20	29	± 20 %
Number of boards per pallet [pcs]	200	134	100
Area of boards per pallet [m²]	144	96.48	72
Pallet weight [kg]	300	300	300
Pallet dimensions	120 × 120 × 200 cm
Storage	on pallets in a dry environment, protect from UV

RETEX, a.s.
U Nádraží 894, 672 01 Moravský Krumlov
www.aquadesk.cz
Photo: company archive