Researchers from the Polytechnic University of Madrid (UPM) have built a roof covered with plants and a watering system that will optimise the consumption of a building’s heating and cooling systems thanks to its insulation. It is a third-generation ecological roof, characterised by its sustainability and the use of indigenous plant species.
“The importance of the roofs”, explained Francisco Javier Neila, Professor at the UPM and co-author of the study, to SINC, “is that each geographical area requires the structures and plant species that work best”. In this case, the researchers divided the roof of an experimental building in Colmenar Viejo (Madrid) into 20 modules, and carried out a test with different supports and regional plants based on three factors: the plant growing at a good speed, the density of the biomass perfectly covering the roof and the result being visually attractive.
Indigenous species work better
In winter and summer conditions, the best performing roof has an 8 cm tank that collects rainwater and offers an even irrigation system.
Plants such as sedum (Sedum praealtum) or aptenia (Aptenia cordifolia) provide the best insulation “because they have a thick leaf and are resistant to frosts and heat”, indicated Neila. But each location where an ecological roof is installed will have its own catalogue of plants, starting with indigenous plants “because in its habitat, the plant performs better”.
The researchers also considered covering the roofs with an effective plant and decorating it with another prettier one to fulfil both requirements, but the result is difficult ,“since when a single space is shared by two species, the stronger one will predominate”, Neila explained.
There are a series of superimposed layers under the groundcover. The first is a very light special substrate which helps to drain rainwater quickly so the plant does not drown. Here, the best solution is pine bark crushed and mixed with sewage sludge.
The substrate lies on porous concrete which acts as a sieve for excess water that will end up in the tank, the capacity of which is controlled by raised floor systems similar to those that support the raised floor of an office. The water contained rises up to the roof through capillary action and enables even irrigation. Just before the building’s floor framing, the roof consists of a waterproof sheet which prevents leaks.
Between each layer an extruded polystyrene sheet is inserted which, according to the roof model, can be situated under the porous concrete or beneath the tank. Each layer also includes a sensor that measures temperature and humidity variables which can be compared with data collected by an adjoining weather station for checking any change caused by the roof during the four seasons of the year.
The researchers have also left various modules without an ecological roof to clearly demonstrate its effectiveness. “Roof areas with plants optimise better the heating and cooling of a building than a normal structure, regardless of how well insulated it is”, the expert commented to SINC.
The design of ecological roofs responds to the challenge of merging urban and rural lifestyles and is being developed in countries such as Germany, Switzerland, the USA and South Africa. Ecological roofs reduce pollution in cities, absorb lead and other organic components. “A forest would be less contaminated with the same intensity of urban pollution", said Neila.
These roofs will help to reduce the temperature of cities, which today are a kind of urban heat island. Scientists have also estimated that acoustic contamination would be reduced to three decibels, thanks to plant absorption.
Groundcover is therefore becoming a new type of building material but development prospects are not positive due to its high price. Neila cites Germany, “where the situation is being resolved with tax benefits, council taxes, increase in suitability for building, which means it does not cost developers so much to invest in this option”.
SINC Team | alfa
Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)
The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research