September 2000 marked the enactment of a variance to Barcelona’s Plan General Metropolitano aimed at renovating the industrial areas in Poblenou, also known as 22@BCN Activity District. The goal was to transform an industrial area in a new technology development area, so preventing the brownfield problem. This implied conditions to rearrange the area, a regulation of land uses and use intensities, rules for public facilities and terms of references for Special Plans.
Built height (the darker the blue, the lower the existing height, with many areas in just 1 level)
When the plan was enacted the area was covered mainly by factories. The proposal was to provide a rise from a floor-area ratio of 2 in the previous zoning to one of 3 in the transformation areas (yellow), the rest (red) rising up to 2,2. This may seem reduced, as it is just 50% at the higher case; but the typological evolution (from one floor factories to narrower, higher buildings) will certainly change the landscape. A part of the increase in built surface is used to pay for improvements in public works.
The cadaster shows little change at first sight; sure, it is not entirely up to date (the “stapler” at Plaza de las Glorias is not yet represented), but the fact is that many projects stalled because of the real estate crisis. The Diagonal façades has transformed, and many projects are changing the area in a rather piecemeal mode, as the MediaTIC building, which opens this post…
French geographer Yves Lacoste used to say that geography is since its inception a war tool. It’s not my aim to contradict him, but in fact urban cartography is since its inception a tool to levy taxes… here are the primary results of processing the cadastral maps of Barcelona by assigning a 3 m height to each level above ground… More soon.
El Viso as seen from the south, according to cadastral data
El Viso is a residential area built in Madrid in 1933-1936 according to the 1925 Low Coast Housing Act. It never really was a worker’s neighborhood, as it soon became an area for middle classes and intellectuals.
El Viso. Lot area (in sq m). Red circles are proportional to the residential floor area for each lot
Nowadays it is a kind of anomaly just by the denser area of Paseo de la Habana- Castellana. The original terraced homes have changed, gaining some levels here and ther, and some are now the location for other uses. However, the layout and the feeling of low density are still there. You can judge yourself thanks to google street view.
El Viso as seen from the east, according to cadastral data. On the background the AZCA towers show their presence.
Central Olivenza. Reference grid: 100 m
Olivenza is a small city in the province of Badajoz, Spain. Until 1801 it was a Portuguese city, and the border is now at a short distance.
This border position is the reason for a series of walls that have protected the city, leaving a still visible trace in the current urban fabric.
The core of the walled zone is organized around the first castle and the main church, with a group of four rather regular blocks. The subsequent urban growth reached a larger wall.
Getting a look at the blocks on the southern edge of the walled area there is a certain degree of regularity, with some 35 m in width and slightly over 100 m in length, and a structure of streets going towards the core of some 5 m in width. Block area is usually between 4.000 and 5.000 sq m (about an acre for Imperial System fans), and lot lines are usually over 6 m. Heights are usually less than 4 levels. The rather narrow block makes courts rather irregular, with not much continuity.
And white architecture, with “calçada portugesa” as paving… A protected area which is well preserved.
A façade on the Calle de Alcalá, Madrid
When you think about façades you think about buildings (one by one, taken as separate items) ; if you think in terms about bocks, the building façade is in a context, be it planar or not…
The façade is in the context of its plan, but also in that of a corner, or related to others in the same street but on the next block. And it is also in the context of whatever happens on the street, be it cars, cranes, horses, ships, you name it…
The façade is just a face of the reality, as it is often rather mute when it comes to describe how deep the building is, or how it relates to the core of the block.
A plan of the same block in Calle de Alcalá (the façade is the one from the white part)
Façades around the corner of Menendez Pelayo and Menorca, Madrid
Façades around the corner of Ibiza and Menendez Pelayo, Madrid. A wider street, a diferent relation
UNESCO published this text, by Alain Borie and François Denieul, in 1984. The World Heritage Convention was enacted in 1972, and the first properties were inscribed in 1978, so this is a rather early text in the production of the “world heritage” concept in its urban derivations.
This is a classical manual, based on the decomposition of the urban tissues in systems: lots, streets, buildings, open spaces… a lot of images in the final part.
According to the Merriam-Webster Dictionary, a block is “an area of land surrounded by four streets in a city”. It is one of the less specific definitions among the languages I have consulted, but it gives a number of four streets, so there is a hint of a quadrangular shape somewhere. The Oxford dictionary, despite a more complex urban layout in Britain, says “a group of buildings bounded by four streets”, but it also recognizes that in America this applies to an area (no need for buildings)… bound by four streets.
What is relevant in terms of architecture and urban planning in a block?
- Size, minimal in middle age cities or Genoa, and enormous in Berlin and other cities.
- Treatment of courts or internal spaces, when they exist
- Permeability between street and court
- The way the street and the lateral façades relate: continuous or not, with varying setbacks by level…
- The shape of angles
- Differences in height between buildings
These are the subjects for the next weeks.
A part of the Texeira Map (1656) in Madrid, in what now is a much denser area.
The transmission of property through heritage can contribute to the urban shape and/or to social structure. Some individual home areas can get densified over time as the need to divide the original lot arises through heritage by a group of brothers, for instance; this is quite more complex with current planning systems in which the subdivision of existing lots can be limited. When inheritance implies an apartment, its subdivision can depend on many elements and be more complex, as creating a new kitchen or bathroom requires a connection to the building’s services that is more difficult to solve in an independent way. This logic (division) makes sense in a growing demography, and also in peripheral areas (it is more difficult in central cities).
What happens when populations decrease, as they do in some European countries? Sure, we have shrinking cities, and then we have Detroit in America. Even if the city loses population, there are chances that the demand for built space will still exist, as it could be driven by other non- residential demands. Many things can happen:
- You can inherit your parent’s property and live there; this has been a common fact in history, and it is worth reminding that demographic growth has been slow over long periods of time, which explains the stability of the urban fabric in many cities up to the industrial age.
- Heritage can become an idle property; as you get no clients, you just have a home that no one uses. This has always existed, but now it could become more common.
- Even in a shrinking city, brothers or other relatives happen, so you could get in a trap as no agreement could be reached between those benefited by the inheritance; in the end, property could again end up idle.
Overall, inheriting in a shrinking city reinforces the use value of a property against its financial value; and you can only sleep in one bed per night (at least under normal circumstances), so if the inherited property is not adjacent to your home you would probably find complex to use both everyday. Conversely, inheriting in a shrinking city can increase the financial value of a property, but you will be able to use it only if you have other properties (you would probably prefer to have at least one sheltered bed every night…) or if you can subdivide the inherited property.
This catalyzer of urban change is real, but incremental. But for a disaster, inheritances are random, both in space and in time, even if you can suppose that a new neighborhood will have replaced its original population in 30-40 years due to old age.
This article by Molina, Rubio and Vecslir is based on academic works, and it addresses the evolution of the retail structures in both Latin- American megacities.
What drives change in the urban tissues? What matters in that question is how diverse the answer can be; there are changes from the bottom up (individual answers to problems that seem personal, but whose sum can produce some kind of “emergent intelligence”), as well as defined from the top of the pyramid (actions defined from the public administration which can lead to direct actions or to mandates to individuals to act in a given manner). Here is a quite concise catalogue of the possible situations, a kind of “table of contents” of what will follow:
- Changes in the dimension of the use unit (households, firms, public facilities…) that mean a change in the physical dimensions of the associated spaces, either through reduction or through extension. For instance, if the number and median size of households rises and urban growth is not possible, what you get are either overcrowded homes or extensions of current homes, either in width or in height.
- Technological changes that imply a larger choice of locations, be it for homes or for other uses. For instance, cars have allowed urban sprawl.
- An evolution of social demand that triggers an evolution in the way the functions of spaces in a typology are arranged. If the demand for balconies increases, home façades will change accordingly, transforming the urban landscape.
- Changes in ownership conditions: a neighborhood in which the residents are mainly owners of their homes can look different from one in which rental is the main condition.
- Top- down
- Political or technological factors determine how the land can be used: if city walls become obsolete, either as a result of the evolution of military technology or of the disappearance of the risk of war, cities can demolish them and extend.
- Fiscal conditions: when some architectural types are subject to higher taxes, this can change the real estate market and the building production.
- Urban planning: plan define mandatory conditions. Paris, Manhattan or Kyoto have particular urban landscapes as in a given moment the decision was taken to organize streets in a certain way and to define how buildings should look.
What is often said to be “the charm of the city” is the combination of all those elements, with varying degrees of poetry and bureaucratic zeal.