AN ASSESSMENT OF THE THERMAL PERFROMANCE OF THE
SEAGRASS POSIDONIA OCEANICA AND RECYCLED ALGAE
PADINA PAVONICA AS INSULATING ROOF BUILDING
ELEMENTS IN MALTA
Angelique Maggi, October 2014
A dissertation submitted in partial fulfilment of the requirements for the award
of the Masters in Environmental Design at the University of Malta
Typically over 25% of a building’s energy losses in a Mediterranean climate are attributed to its
flat roof. In such buildings, the roof may cover over 60% of the building’s surface. Any action to
improve its thermal performance will go a long way towards energy efficiency. This study
focuses on testing a sustainable way to reduce heat gains through the roof by using the seagrass,
Posidonia oceanica, and the algae, Padina pavonica, as the insulating element. In the past
Posidonia oceanica was found to be effective as roof insulation by coastal communities and
hence assessing its potential for re-use as an insulation material is of significant importance.
Padina pavonica, once processed, has been found to have medicinal properties and the remaining
waste at the end of the process is a powdery material known as, Padina cake. The study reuses
the Padina cake as an insulating material and compares its thermal performance to that of the
Posidonia oceanica. The study investigates the U-Value achieved using these materials in local
building practices. This is done by testing out dried samples of Padina cake and Posidonia
oceanica in their raw form, without any additives, using the calibrated hotbox method. Results
indicate that these materials possess insulating properties and that there is potential for further
study.