Let’s go back to the inception. The project for the urban extension of Madrid was prepared between 1857 and 1860 by Carlos María de Castro, including the current Barrio de Salamanca, and set to take Madrid from 270.000 to 450.000 residents in a century. Altough people still talk of the Castro Plan (planners, as there has been not an extended knowledge among lay people as in Barcelona), it has become, as well as in Barcelona, quite different from the initial plan, even if the structure and the idea of a grid is clearly there.

The Castro Plan (Anteproyecto de Ensanche, enacted july 19, 1860) established a maximal height of 3 levels (ground floor+2) with a maximal ground ocupation of 50% of the lot area. But in 1864 the Government increases height from 3 to 4, reducing the space for courtyards and gardens to 30% in lots over 10.000 sqm, and to 20% in lots with smaller areas, allowing private streets to be counted as such. 1867 is the year in which the old city bylaws come to be applied to the extension area, rising so height to five levels plus penthouses. Castro is substituted as chief officier for the urban extension of Madrid in 1868, and in 1873 municipal bylaws reduce street width, supress gardens on private spaces, and legalize any previous building. And as in any administrative bad joke, the Definitive Extension Plan (the 1860 plan was deemed to be a draft) is aproved in 1898, when a substantial part of the extension was already built.

The Castro Plan aimed to get to a ratio of 50,98 sq m of built area per resident for the whole of the urban extension, improving the then current ratio of 28,68 in the old city. Nowadays, and taking only the Barrio de Salamanca on the part of the same name ward that is west of calle Francisco Silvela, there are 83.000 residents and 282 persons per hectare (residents only). Cadastral data say there are slightly over 6 million sq m of built area for housing, so there are some 73 sq m of housing per resident. Way ahead of what Castro aimed for on average, altough this figure masks strong variations…