Experimental Green Rooftop

Our experimental rooftop is located on a Building at the Ciutadella campus of University Pompeu Fabra (UPF). There are three experiments in parallel. If you would like to visit the rooftop, we would be delighted to show it to you.

The first experiment is a comparison of different green roof systems. Each manufacturer has installed its propietary system inside a thermally insulated planter. There are two types of green roof being tested: extensive (with sedum) and semi-intensive. We are measuring energy efficiency (via temperature) using four probes installed at four different depths in each sample (on the ground, in technical layers, in the growing medium, and at the level of vegetation). The experiments started in January 2016 and will last one year. They are comparing different solutions with respect to their price, weight, water requirements versus green growth and energy efficiency as well as the capacity of water collection and filtration of pollutants the atmosphere. The different green roof systems have been provided directly by the manufacturers: Igniagreen, Renolit, Urbanscape, Green-cover, Projar i Zinco. The last one is also a join effort with Vallimper, Ingenieria de Cubiertas Verdes, Jardinatura and Massoni.

In addition to the collaboration with UPF, this experiment is being performed primarily with the Polytechnic University of Catalunya (UPC, School of Construction) and secondarily with the Institute of Environmental Science and Technology at the Autonomous University of Barcelona (ICTA-UAB). Thanks to a grant from the Metropolitan Area of Barcelona (AMB), we have two building engineers who will continuously monitor the experiments. Finally, this rooftop received a subsidy from Barcelona City in 2016.

The second experiment is a pilot to test the ideal growing conditions for lavender. Eixverd launched the experiment in September to assess how different types of lavender respond to a variety of growing mediums in an urban rooftop environment.

The long-term goal of the project is to carry out medium- to large-scale cultivation of lavender on buildings and parking lot roofs in the Eixample district of Barcelona. Related to this experiment we also have a section growing different varieties of aromatics.

The third experiment is a comparison of different soils (growing media) of agricultural rooftop and has been operational since March 2016. The agricultural soils for rooftops have different characteristics from those of a traditional garden and growing table soils. The drainage, the weight saturated with water, soil stability, and compactness should be different when planting directly in the ground versus in growing tables.

Through our collaboration with Brooklyn Grange Farm and conversations with other agricultural rooftop organizations in Europe, we are testing various commercial growing media and various composts. One of the samples uses Zinco system along with a soil from Bruc Jardi. The other samples use Projar system and soil. Another variable we are measuring is the ideal soil thickness, with the output variables of productivity, water requirements, and maintenance.

The experiment will also determine the substrate that could be used for the Dipòsit de les Aigües  rooftop.