Stacked Balconies


A facade in precast concrete elements wraps the structure of the Piraeus Tower and introduces a notion of mass. A pixelised texture of two different sizes of openings breaks with strong verticality of the skeleton.

The openings are occupied by three different types of openings:
Type A: A simple window
Type B: A box-type window consisting of a simple window in combination with a exterior glass panel. This window type operates as a natural ventilation device. The hot air in the buffer zone rises and evacuates air from the interior spaces.
Type C: A balcony between a recessed window and exterior glass panels. The balconies create natural ventilation as well, but only if several of them are stacked on top of each other forming a sort of chimney.

Each window is assigned a window type according to the three main environmental parameters: Noise, sun and wind. The data describing these parameters is translated into image maps. Using the RGB additive color model, all information can be condensed into to a single image.


A script evaluates the parameters for each window position. A lot of noise or wind demands a box-type window that offers more protection than just a simple one. Where the sun intensity gets more important than noise pollution or wind forces, a simple window is preferred because it diminishes the danger of overheating the interior as there is no heat radiation from a heated thermal buffer space. The balconies are only placed in areas without strong noise so that they always offer a calm recreation space. Once the window types are assigned, there’s a recursive function that analyses the stacking of the balconies that is required to contribute to the natural ventilation of the building. Only stacks of at least three balconies are admitted. The remaining balconies are reassigned and become openings of type A or B.
Then an other script places the exterior glass panels in front of the balconies. These glass panels have their own rhythm that is independent from the rhythm of the openings. The glass screen becomes an autonomous layer added to the perforated concrete facade. These two facade layers are working together and against each other at the same time. The resulting panel pattern gets analyzed and recursively modified within the script: Where there are columns of at least six panels on top of each other, the proportions of the thermal buffer required to produce a chimney effect allow an increasing depth of the balconies.

A heatmap illustrates the ventilation covering of each floor by analyzing the distances to the next ventilating window. This feedback allows to detect problematic zones and react to the lack of ventilation by changing some initial parameters (like for example the number of windows, their dimensions or the ratio between small and large windows) or simply by re-running the original random window repartition. The information made visible by the heatmaps defined the location of the security stair on the south eastern facade. The shaft created by the stairs contributes to the ventilation and covers an area that was marked by a deficient natural ventilation.

The plinth with it’s regular window interval is wrapped with glass panels as well. These glass panels are placed by a random based engine that takes in count three layers of information that modify the chance of a panel being placed for each possible panel position.
The trhee layers are:
1. A vertical gradient producing a ‘curtain effect’ (high density of panels at the top, lower density towards the ground)
2. The street noise (more panels along the main road and the parking entrance as acoustic protection)
3. A set of entrances, exits and passages that have to stay panel-free.
As a result, the completely liberated ground floor become a protected public space that works as an extension to the nearby market.

The glass curtain wrapping the plinth unifies the tower with it’s base and grounds the whole building.

Facade detail

The relation between the new facade with its recessing loggias and the existing concrete skeleton is critical in some configurations. The following taxonomy lists the different possible constellations. Some of them might demand a adaption of the shape of the balcony to avoid useless spaces or perhaps even to take profit of the pillars as a spatial divider.


Grasshopper definition

Grasshopper screenshot

One comment:

  1. [...] The window types are assigned as described in the last post: [...]

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