The Princeton Envelope Group (PEG) is a design and research unit at the Princeton University School of Architecture. Headed by Alejandro Zaera-Polo and coordinated by Urtzi Grau. The unit is engaged in a three year research program on the Politics of the Building Envelope the conclusions of which will be published in a forthcoming book by Actar Press, Barcelona+New York.


The vertical envelope has a predominantly vertical dimension and, unlike the flat-vertical type, a multidimensional orientation in plan. The specificity of this envelope category is an intense relationship between physical determination and performances. Because of its scale and technical complexity, functional and environmental performances such as daylight penetration and natural ventilation need to be maximized, while the formal qualities of the envelope play a crucial role in the building’s structural stability. The vertical envelope’s geometric determination crucially impacts both the spaces that it encloses and its surroundings. In addition, the visibility of the vertical envelope makes it particularly conducive to iconographic performance. If in the spherical envelope the gap between representative and environmental performances reach a maximum, in the vertical envelope both sets of performances are at their highest level. The collusion between extreme technical performance and high visual impact produces maximum tension between efficiency and expression, a condition that runs deep in the history of this building type.