Irrigation of Roof Terraces in 8010 Graz

Citygreen, an experienced expert in the greening of buildings, roofs and green spaces of all kinds, could only start planning the greening of the two roof terraces in the city center of Graz after the building was completed. In general, however, the earlier the planning of the irrigation technology is included in the construction planning, the easier and cheaper the implementation.

In the case of the first apartment, extensive greening of the roof garden was initially planned. There have also been no water connections. Then came the desire for finished turf on about 100 m2.

Due to the statics, only a very low substrate height of 15 cm (including an undersized water reservoir) could be planned. It was therefore essential for the planning of the irrigation system that the lawn be supplied with moisture exactly when and only when necessary. Exactly on time, because this is the only way to avoid wasting water. For challenging projects, Mr. DI Hubert Trixl is happy to consult the irrigation specialists from Prochaska. Because an additional challenge was the low water flow pressure on the roof of the house: 1.8 bar – only about 10l of water per minute. That was almost too little for automatic irrigation.

The Prochaska | TORO irrigation team used hydraulic calculations to determine the exact amount of water needed and planned the irrigation precisely taking into account other important parameters such as soil structure and shade in this case. Prochaska put together a system with very short (5cm) pop-up sprinklers from TORO. Essential was the installation of the TORO Evolution® control unit with a weather station. This ensured that the lawn plants were optimally supplied with water in all weather conditions.

In addition to a lawn area, the second green roof was to have larger plant troughs with cherry laurel and small trees. Here, the Prochaska | TORO team, together with CITYGREEN, decided on the combined use of drip irrigation of the plants in the troughs and again short sprinklers for the lawn area.

For an optimal result and maximum water savings, the professional installation of an irrigation system is essential, in addition to optimal planning. Under such conditions, the high precision of TORO control units and modern irrigation nozzles reduces water consumption by up to 30% compared to conventional systems.*


Here, two irrigation solutions tailored to the needs of green roof terraces were successfully implemented under very tight specifications.

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