Mexico is one of the most urbanized countries in the Global South and simultaneously faces a rapidly increasing population and a deluge of inadequate housing (URBANET 2019). In 2016, it was estimated that 40 percent of all private residences in Mexico were considered inadequate by UN-Habitat (UN-Habitat 2018). As informal housing constitutes over half of all Mexican housing construction, the most vulnerable groups of the population are particularly impacted. Therefore, there is a serious need to innovate in the area of low-cost building construction for housing in Mexico. This research explores how shape-optimized concrete and earth construction could help provide adequate housing without jeopardizing the country’s commitment to sustainability.
In particular, this project focuses on innovations in structural floor systems, due to their typical material intensity and potential for improvement. In multi-story buildings, most of the structural material is used in horizontally-spanning elements such as floor slabs (Huberman et al. 2015; De Wolf et al. 2016). Between 60 and 80 percent of the mass and embodied energy of a multi-story building’s structure can be found in the floors (Foraboschi et al. 2014). Due to the relatively high cost of materials, many affordable housing projects in Mexico utilize the beam-and-block (vigueta y bovedilla) system for horizontal spanning elements. It is a construction method that uses lightweight precast (and occasionally pre-tensioned) beams with lightweight blocks (typically concrete, extruded polystyrene, or other low-strength materials) that span between the beams to provide lost formwork for a castin-place slab. This solution has been in use for decades and gained popularity in Mexico because it relies on small, lightweight precast elements removing the need for on-site props, and large machinery. However, the existing system prioritizes speed of construction and repeated, overdesigned modules at the expense of material efficiency, offering opportunities for material and carbon emissions reductions through a more careful allocation of materials and embodied carbon.