Sustainability of Traditional, Historical Roofs in the Mediterranean: A Rediscovered Opportunity for a Carbon Neutral Future

As the world grapples with the effects of climate change, there is an urgent need for sustainable solutions to help reduce carbon emissions. Historic urban centres can indicate one possible way forward, and this is because of the way traditional buildings (in this paper centring on the Mediterranean) are built. Their materials and technologies are usually well chosen and adapted to hot climates, while the layout of historic centres, often with quite narrow, winding streets, provide shading and frequently also appropriate direction of cooling winds, especially in marine locations. These often result in these urban cores being cooler than more modern city centres. Traditional roofs, in particular, have over the centuries proved to be reliable and sustainable (when given appropriate maintenance), with layers of porous materials providing inbuilt breathable (evaporative) properties. These lead to a degree of passive cooling and ultimately to less energy consumption (less use of air conditioning for example), thus creating a smaller carbon footprint for each building, and hence also for the urban centre when a number of these buildings are present. This paper is based on a three-year pilot study, where an innovative methodology using a combination of remote data (obtained from Unmanned Aerial Vehicle (UAV) and satellite) with in situ measurements, allows for the remote identification of traditional and modified roofs, as well helping understand the thermal behaviour of such roofs, with this study concentrating on historic centres in the Island of Malta, in the Mediterranean. Ultimately aimed at promoting preservation of these traditional roofs, this study provides data to help address, at least in part, current climatic concerns, whilst also potentially providing some adaptation strategies to address climate change (in particular increased ambient temperatures). Our studies on the behaviour of traditional deffun mortar roofs have shown that they are effective in protecting the internal environment from the external one. This can lead to a reduction in carbon emissions and help create a more carbon-neutral future over an entire historic centre. Therefore, in the long term, with the right management policies in place, traditional roofs on traditional buildings can provide an excellent and cost-effective way of moving towards carbon neutrality in historic urban centres.