Good planning’s the key.

Our calculation software helps you make decisions.
When planning your green roof, imagine you already knew how weather conditions would develop over the next 20 years. Or what quantity of rainwater to expect in the short, medium or long term. Or how much water you’d need to irrigate your green spaces. When you design your project, this information would give you a significant competitive edge.

Calculate water resources for better urban spaces

The ClimaGrün assistant can calculate water resources based on historical, current and future climate data.

ClimaGrün and the Fraunhofer Institute develop software that calculates factors relevant to green roof planning, based on historical, current and future climate data. The software draws on all ClimaGrün’s intelligent green roof system products, such as substrates, fleeces and water retention layers. It can even base its calculations on third-party products.

Take the guesswork out of planning. The ClimaGrün assistant gives you all the information required.

Rainfall data analysis

Past and present rainfall data close to the site is analysed and future rainfall data established.

Irrigation water calculation

The water required to irrigate the vegetation is calculated.

Water balance modelled

The water supply is calculated and analysed.

Evaporation performance calculated

The evaporation performance of the green roof system is calculated.

Roof drainage solutions calculated

Calculation of the roofing outlets under normal and emergency drainage conditions pursuant to DIN 1986-100.

Dimensioning of the water retention layer

To ensure an optimum thin water storage layer, its capacity is established based on local rainfall data and evaporation calculations.

We can compute your green spaces accurately and provide the supporting documentation.

Collaboration with the Fraunhofer Institute

ClimaGrün gives planners, landscape architects and garden designers a practical tool, based on sound data, to help make decisions. The results facilitate better assessments of proposals submitted in tenders for large-scale green building projects in urban spaces.

How to use the ClimaGrün assistant


Getting into contact

Contact us. You’ll gain an impression of what we do and we’ll have a rough idea of your requirements.


Sending information

Send us all the documents required for your project. Why not use the ClimaGrün configurator and forward your project number to us?



Now the ball’s in our court. Our software will get started and you’ll quickly receive what you need for planning purposes.


Done the maths

The automated calculation has been completed. You’ll receive relevant data, recommendations and results plus all the supporting documentation for your project.

We’ll pave the way to your green roof projects. Innovative tools, an experienced team and 20 years’ experience help you to plan, find ideas, make decisions and pull your projects off efficiently and sustainably.


Green roofs and surfaces are planned by landscape architects, general planners, etc. in collaboration with ClimaGrün.

To best plan a leading-edge green roof, it’s important to look at all the project requirements. This includes analysing local rainfall data to calculate the quantity of water needed to irrigate the green roof and draw up a water balance. A suitable system solution is then selected that offers sustainable and local use of rainwater and plenty of greenery due to high-quality plants.

Just send us your CAD file and we’ll do the rest.

To exploit such a valuable resource as rainwater to the full and to avoid using drinking water to irrigate the greenery on the roof, long-term studies and forecasts are relevant when calculating water requirements.

By storing rainwater on the roof, water is retained and therefore puts less pressure on the sewers. Without consuming much energy, the rainwater can be reused to irrigate roof vegetation, which boosts the natural water cycle in urban spaces. Vast quantities of water can also be stored in thin layers on the roof, dispensing with the need for large water tanks. Why not find out more about this issue in our article on The Retention Roof – a Core Element of the Sponge City?

Climate change and rising temperatures will, in particular, cause more heatwaves and heavy rainfall. Rainfall will occur less frequently, but be heavier. Why not find out more about these issues in our Urban Climate Change article?

In standard cases, a retention roof can hold up to 140 litres of rainwater per m². The quantity of water required for optimal irrigation is first calculated for each green roof.

This depends significantly on the greenery and weather conditions.

We look forward to receiving completed projects from architects, landscape architects and contractors, which we’ll be happy to publish, including links and the names of everyone involved.

In the past, green roofs were usually not watered at all. And if they were, it was with drinking water. Plants that often don’t require watering, such as sedum, no longer meet the requirements regarding biodiversity, evapotranspiration, etc. As irrigating intensive green roofs or surfaces with drinking water will no longer be permitted in future, it’s better to avoid doing so now if possible.