This paper contributes to the classification of urban form on the basis of variables arising from its morphology–buildings, plots, blocks and streets–, taking the case of the Metropolitan Area of Barcelona as a case study. New density attributes regarding street alignment and party walls are introduced together with the most common floor and ground surface indexes. The algorithm k-means is used to perform a cluster analysis. The results reveal a clear mosaic of urban fabrics, composed of 12 dissimilar groups. The combination of the outcomes with other non-physical parameters–socio-economic indicators, energy and equity, among others–is suggested with a view to evaluate urban form effects.