The aim of this work is to measure quantitatively the impact of intensive residential densification over the morphology of the urban fabric in the selected neighborhoods in the Metropolitan Area of Santiago. This is made through the review of different constructability indicators, expressed both in building permits as well as in the respective Communal Urban Plans. Complementarily we seek to understand to what extent some laws of exception such as "plot merging", "harmonic set" and "DFL2", weaken the capacity of communal regulatory plans to lead growth and urban transformations. These benefits allow additional percentages of constructability that exceed what is established by current Urban Plans, which in sum can significatively distance themselves from the urban planning vision defined for the city. The benefit of "plot merging" considers an increase of a maximum of 30 % and for the "harmonic set" it ranges between 30 and 50 %, depending on the conditions of the property to be densified. Meanwhile, for the benefit of "DFL2", the increase in constructability considers a maximum of 20 %.