Beijing Blue Roofs
According to Sinapolis Studio, Google Earth images of a randomly selected hutong block of 0.5 km ² indicate some sobering developments for Beijing’s traditional alleyways and courtyards from 2002 to today. The “profiled insulated” steel sheet, an inexpensive material made from steel and polystyrene, easily obtained and regularly proffered by local construction firms, has spread prolifically in Beijing’s downtown areas. In 2002, in this block, only three structures (likely temporary), had this type of roof. In the past, such materials were typically prefabricated and associated primarily with construction sites in the process of transition. In 2011, the number of these blue roofs has sky-rocketed as the use of this material has become more common.
The saturation of blue on the images shows quite clearly the increasing number of informal buildings in these historic areas between 2002 and 2011, yet they may no longer be an indication of supposedly temporary structures or additions. Confronted by the various challenges of obtaining building permits, a lack of consulting intermediaries that might aid in increasing construction quality and the inevitable need for expansion, the choice seems clear for many homeowners. Consequently, buildings originally meant to be temporary become permanent, while the materials used frequently become less sustainable.