An assessment of the thermal performance of the seagrass Posidonia oceanica and recycled algae Padina pavonica as insulating roof building elements in Malta

Abstract

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 processes 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.