ABSTRACT
Structural stability, thermal comfort and reduced environmental impact are among core objectives of any building project. Typically, those objectives are addressed by three or more discrete systems, for example a structural frame, insulation and onsite energy generation. Some systems, however, are able to satisfy all three objective domains in a single element, using massive natural materials with structural capacity. Stone, earth and timber, for example, all have considerable load-bearing capabilities, while also enabling heat storage and lagged release, in combination with exceptionally low carbon footprints due to their light processing requirements. Within this context, the paper explores design opportunities in those systems through three case studies in vernacular construction, focusing on three materials in three distinct climate zones. The first case is hill dwellings in the region of Ourense, Spain, in a continental and humid Atlantic climate, where solid stone in mud mortar is employed for wall structures that double up as envelope. The second case examines rammed earth structures in Ouarzazate, in the desertic climate of the Moroccan Atlas Mountains. The third case analyzes timber structures infilled with a mix of adobe block and fired brick in Bungamati, in the Kathmandu Valley of Nepal, characterized by a monsoon sub-tropical climate and by a high seismicity. All three building typologies emerge as a clear response to the immediate environmental context. Locally available, low energy materials are combined to deliver a single construction system: an efficient structural form for carrying gravity and environmental loads (including high seismic loads where applicable) that is capable, simultaneously, of providing a climatic barrier based on high thermal mass. The thermal performance of the three systems is compared through a simplified dynamic thermal analysis using DesignBuilder. An environmental context concept framework is developed to identify contextual characteristics that influence the built form and extract design principles that could be applied in contemporary construction. The analysis highlights the necessary collaborative nature of designing these combined single systems. This is a process that has the potential of bringing together engineers, building physicists and architects right from the very early stages of the design.
