Tipping point

In a rural area near Asunción, in Paraguay, Javier Corvalán has created a country retreat for a film director that through a simple but ingenious tilting mechanism does away with windows by opening up to the surrounding landscape.

This article was originally published in Domus 968 / April 2013

“At the beginning,” says Javier Corvalán, “this house was the antithesis of our usual way of doing things, since we had chosen a physical factor as our point of departure, instead of starting from a material and structural question as we normally do.” The exception may perhaps be ascribed to the fact that this house — built for a famous Paraguayan movie director — induced the architect to be swayed by a topic that has always fascinated him: the properties of light.

With this inspiration he developed his design as an optical device, a sort of “camera obscura” into which the upturned image of the surrounding landscape is projected through a pinhole. This idea might initially sound like a gratuitous ploy, but in truth, the chosen solution is perfectly suited to the building’s functional programme. The project can be summed up as two simple parts: a base housing the bedroom and bathroom, and an upper volume with the kitchen and living room.
The Caja Oscura (“camera obscura”) house lies in a rural area about 15 km from central Asunción. Built for a couple who are often away, it is comprised of two main elements: a base of concrete and stone sourced from a nearby quarry, and an upper boxlike structure in plain galvanised corrugated sheets
The base in local sandstone supports the loads of the concrete-tiled floor and upper volume. An interior staircase composed of cantilevered stone blocks leads up to the “camera obscura”. On closer examination, one finds that this upper volume is actually a mobile, metal-framed structure, clad on the outside by plain galvanised corrugated sheets, and on the inside by thermal insulation and MDF panels.

The main feature of this metal box, and the most curious thing about the whole house, is the mechanism that allows it to swivel on a pivot offset from the longer side of the building. By inertia, the volume breaks away from its balanced state and opens up to the landscape, thanks to a simple manual winch that operates the opening and closing mechanism.
Javier Corvalán, Caja Oscura, Asunción, Paraguay 2013
Corvalán’s project also included an embankment, which is now awaiting completion. Built for clients who spend most of their time abroad, the house is left unguarded for long periods and abandoned to the invasion of luxuriant flora. For this reason, having constructed a new topography, it was decided to concentrate the building operation on a limited portion of the site and to let the surrounding vegetation run wild. The aim of the embankment is to keep the house’s lower level cool and dry in the hot season. In addition, its inclination is exploited to create a ramp, facilitating access to the day zone for a disabled member of the clients’ family while they are away.

The logic behind the development of the tilting metal box deserves further consideration. In its search for balance — or imbalance — between weights, its design sets out to exploit certain elementary laws of physics that, when suitably harnessed, allow the volume to be opened and closed. In this sense, the project recalls a celebrated solution adopted on a smaller scale by the Brazilian architect Paulo Mendes da Rocha for the windows of his home in Butantã (1964). They, too, were conceived to rotate around a pivot that was offset from the centre of gravity.
A manually operated winch and a system of tie rods serve to actuate the mechanism that opens and closes the metal volume, which can be tilted to an angle of 25° from the horizontal
Accordingly, one may view Corvalán’s approach as having a certain affinity with the experiences of architects such as Eladio Dieste, Clorindo Testa, João Batista Vilanova Artigas, Antonio Bonet, Affonso Eduardo Reidy and Mendes da Rocha himself, to mention just a few.

These figures are also revered as “masters” by an entire generation of Latin American architects who are united by the conviction that structure can and must be a combination of space, form and matter. That conviction is particularly applicable to Paraguay, where the highly limited resources must be used sparingly in any given situation, dictating the fundamental need to make rational choices.
Javier Corvalán, Caja Oscura, Asunción, Paraguay 2013
Maximum economy must therefore be combined with functional plans, local geographic and climatic factors, and available building materials and techniques. In this case, when the movable upper volume is closed, a sensorial and poetic atmosphere is created by the “camera obscura” effect, inundating the interior with the upturned image of the surrounding nature. Yet it only has to be opened again to solve some of the project’s functional and spatial issues.

The focused references to tradition also serve a precise purpose. On average, Paraguay has 285 days of sunshine per year, with temperatures often reaching 40° Celsius. The comfort of shade is thus a necessity, and precisely for this reason the porch is a key feature of traditional Paraguayan homes, where it serves as a ventilated family meeting place sheltered from sun.
The metal box lid has a cross-shaped structure consisting of iron tubes. It is clad on the outside with corrugated sheet metal and on the inside with MDF-type panels
Corvalán has always deftly reinterpreted and reinvented the quality of this space, but, due to economic reasons, in this project he could not increase the house’s dimensions. Nonetheless, in the rotational movement of the upper volume, he has managed to include this region’s typical sense of spatial progressiveness — open, half-open, closed — thereby regulating the natural ventilation of the building and defining its relationship with the surrounding landscape.

Furthermore, in a country like Paraguay, where profound social and economic differences and consequent criminality represent a source of ever-present insecurity, the clients’ long absences would have exposed the house to obvious risks of burglary and vandalism. The almost total absence of windows is not only due to the necessity to cut costs, but also responds to the need to make the house less vulnerable. Thus when the upper volume is in the closed position, the building becomes an impregnable, hermetic box.
For this building, Javier Corvalán drew inspiration from the profession of one of his two clients: the film director María de la Paz Encina, whose best-known work, titled Paraguayan Hammock, was shown at the 2006 Cannes Film Festival in the section “Un Certain Regard”. Corvalán thus turned the upper volume of the house into a sort of “camera obscura”, with an upturned image of the surrounding landscape projected into the building through a pinhole
While at first sight the solution adopted here might seem gratuitous, in reality it responds to real necessities in the economy of a project which, aside from its peculiarities, is wholly expressive of Corvalán’s output. The tight budget — in this case just 20,000 euros — in no way restricted his imagination. On the contrary, it stimulated a quest for new answers. In Javier Corvalán’s Laboratorio de Arquitectura, to tackle a project means to reflect on the act of constructing. This exercise is carried out by attempts and experiments, by proportioning weights, structures and spaces and testing new states of equilibrium which, however, always accommodate the functional, spatial and distributive requirements at hand, without sacrificing a precise poetic philosophy. Giacomo Favilli, architect, lives and works in Asunción, Paraguay
Javier Corvalán, Caja Oscura, Asunción, Paraguay 2013
Javier Corvalán + Laboratorio de Arquitectura: Caja Oscura
Javier Corvalán + Laboratorio de Arquitectura
Design Team: Nicolas Berger, Carlos Agüero, Joaquin Corvalán, Katja Kostrencic
Structural and Plant Engineering, Construction Supervision: Javier Corvalán
Client: Paz Encina, Ignacio Telesca
Built Area: 85 m²
Cost: € 20,000
Design Phase: 2011
Construction Phase: 2011–2012
The Paraguayan architect Javier Corvalán photographed in his office. Born in 1962 in Asunción, he graduated in 1987 from the Universidad Católica Nuestra Señora de la Asunción, and went on to specialise at the Sapienza University in Rome. He is visiting professor at numerous schools of architecture, including the IUAV in Venice. Corvalán has twice been a finalist at the Ibero-American Architecture Biennial

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