Due to the climate crisis numerous municipalities have introduced new and stricter rules to reduce soil erosion and degradation.
The aim of this is clearly to reduce the rate of rainwater flow from impermeable, man-made collection points into rivers and streams, thereby reducing erosive phenomena.
Green roofs contribute to this goal by offering a highly efficient substitute for permeable areas which are required by building regulations.
And far beyond the environmental benefits the cost of a green roof is offset by reducing the need for a large building surface-area making it economically advantageous too.
Today, incentives in the form of subsidies and tax breaks exist for the installation of Green roofs.
A large part of energy efficiency and housing performance depends on the roof of a building. And most importantly, it needs to be highly durable.
There are numerous technical regulations regarding its construction. Today, green roofs have a technical standard: UNI-EN 11235: 2015 which provides design indications, technical characteristics of single components and rules to evaluate its overall performance.
The most important aspect in evaluating its environmental performance is Runoff coefficient, defined as the ratio between drained and incident water, in a unit of time.
The UNI-EN 11235 standard sets it equal to 0.6, measured in normalized rain conditions, (referred to the FLL: 2008 directive, which defines its duration and intensity).
All FertilRoof systems are the result of careful design and choice of components and are particularly geared towards overall performance.
Runoff coefficient evaluations are calculated through rigorous testing in our experimental rain chamber or in external laboratories with proven experience in the sector.
The result is reliable, long-lasting roofs which help protect and enhance your investment.
Cumulative rain data FertilRoof WRP Extensive referred to m2 – Rain intensity 108 mm h-1
FLL assessment procedure: 2008
Runoff coefficient UNI 11235: 2015 = 0,5
Substrate thickness = 80 mm
UNI 11235 limit = 0,6
Synthetic extract of the test report by the MAC laboratory – Minoprio Analysis and certifications – Minoprio Foundation – Lombardy Region.
The graph illustrates the runoff of water from the FertilRoof WRP Extensive System, after the simulation of a rain event of maximum intensity.
The measured value meets with margin the performance requirements established by the UNI 11235: 2015 standard