Casa Osa

Cerro Osa, Costa Rica - 2013
12. January 2015

Casa Osa

2013
Cerro Osa, Costa Rica

Client
Withheld

Architect
OBRA Architects
New York, NY, USA

Design Principals
Pablo Castro

Project Architect
Shin Kook Kang

Project Team
Atsushi Koizumi, Patricia Bohrer, David Karlin, Doreen Lam, Jennifer Lee, Edina Nathania

Structural Engineer
Robert Silman Associates

Contractor
Brad Shenko

Site Area
98 hectares (242 acres)

Building Area
375 sm (4,000 sf)

Photographs
Peter Lynch

Drawings
OBRA Architects

For the last two years the Buildings of the Week on the U.S. platforms of World-Architects looked at one building in each state over the course of fifty weeks. For 2015 we are going a different route and looking at buildings overseas designed by architects based in the United States (occasionally we will present the inverse, buildings in USA designed by architects from overseas). The first installment in this feature is a vacation house in Costa Rica's Osa Peninsula designed by New York's OBRA Architects. The pleasant climate led the architects to craft a composition of open-air rooms and walkways underneath a complex roof form. OBRA Architects answered a few questions about the project.
View of courtyard and stepped ramp to living room
What were the circumstances of receiving the commission for this project?

OBRA Architects was recommended to our client by a friend of his who attended a lecture we gave at the Museum of Modern Art in New York.
Living room elevation
Please provide an overview of the project.

This is a vacation retreat for an American doctor and family on the Osa Peninsula, the realization of a client’s lifelong fascination with wilderness and desire for life in proximity of exuberant nature. Located on 98 hectares of virgin rainforest with views east to Golfo Dulce and west to the Pacific, the house occupies a small hill, formerly a mango farm, avoiding the need to destroy trees. Moving down the hill, different wings orient themselves rotating in plan as they descend, privileging with their discrete axes of symmetry multiple points of fugue to structure views of the forest around with silent invisible geometries. Two walled gardens defined by low walls provide transition between “interior” and exterior, outdoor zones safe to use in evenings when snakes freely roam about.
Entry with view to kitchen
What are the main ideas and inspirations influencing the design of the building?

The arrangement proposes a controlled but unstable tension between house as object and space of the forest as site. Rather than freestanding element surrounded by leftover land, or boundary-like architectural arrangement encircling courtyards, it gives neither primacy to object nor space. The house retains integrity of a single architectural volume seen from outside, as the pavilions overlap in depth, flattening perception of spaces in-between, yet as one enters, vistas of forest and sky between pavilions make it hard to discern if surrounded by one structure or many.
View through snake-free courtyards
With its remote location and tight budget, the house was designed to achieve the following 5 main points:

1. Desire for a measured, respectful proximity to the forest

2. Definition of spaces for warm climate year-round, protection from sun in summer, from rainstorms in winter

3. Utilizing topography to closely approach corners of the forest, to generate psychological house map with intuitions of Up, Down, Gulf-Side, Ocean-Side, etc.

4. Open architectural plan encircling and framing landscape, allowing winged wildlife to traverse throughout

5. Method of construction flexible enough to create complex roof forms suggested by demands of the plan, the hill and topography, yet simple enough to be built by local labor in remote location.
View to living room
Were there any significant challenges that arose during the project? If so, how did you respond to them?

The most difficult challenge for the project was the design, detailing and construction of the triangulated sections of roof suspended over the ramps and stairs connecting the different sections of the house. The project was to be constructed with the help of locally based workers and the proposed geometry, although not particularly complex, was unfamiliar to their experience. Furthermore, due to the remote location of the site, the building crew would have to camp on location during the construction of the house and have with them all the materials and tools necessary for the successful construction of the project. Frequent, or even sporadic trips to the hardware store were impractical given that the nearest one was located an eight-hour-drive from the site.
Pacific Ocean beyond
Two different structural solutions were designed to solve this problem, one contemplating a steel tube structure connected through a series of pre-fabricated steel hubs we called “spiders” and an array of adjustable brackets that, shaped like rings around the tubes, were capable of rotating around them until finding a point in the geometry that would allow them to connect beams and rafters. This system proved impractical since the “spiders” became a too dense point of material concentration where making the necessary connections was difficult.

The second and final structural system proposed the creation of composite beams for every member. Each beam was formed by two back-to-back steel “C” profiles sized according to their span and connected to each other by steel plate brackets that gave them the desired configuration and that had the advantage that could be bent to the right geometry on the site. All the joists were then fastened to the profile’s flanges.
View toward Golfo Dulce
How did you approach designing for Cerro Osa/Costa Rica and how would you describe the process of working on the project there?

Three different factors contributed to the final form adopted by the building:

1. Located in an isolated corner of the world, on top of a hill and surrounded by dense forest, we felt the house needed to have some of the variety of choice of personal location that is more typical of urban environments. In other words, the world created by a compact building in the landscape is typically reduced to one of two possibilities, either inside or outside. One of the reasons for the organization of the house in five discreet elements is a desire to use these in the definition of exterior spaces that, lying between them, can contribute to the creation of a more varied range of possible personal locations in relationship to the house and its setting, not only inside or outside but also something like inside-inside, inside-outside, outside-inside and outside-outside.
Detail view of roof
2. On a piece of virgin forest measuring 89 hectares, the hill where the house sits, an area of approximately 90,000 square feet, is the only spot that has seen human occupation in the past and is thus the logical place to site the house from an ecological point of view. During the design process the memory of Frank Lloyd Wright advising architects never to place a house on top of a hill — perhaps because he thought it would mean a disrespect to nature, the source of all authority in the world — was accompanied by the realization that he also refrained from suggesting exactly where, down the side of the hill should the house be located. Instead of guessing and getting it wrong, we thought that it would not be a bad idea to stretch the house, so to speak, along the entire side of the hill to cover all possible options.
Sketch
3. We were attracted by a plan arrangement that replicates exactly the cinematographic tradition of alternating action shots that move forward the narrative of a film with quiet shots that act as meditative moments of relief in an ongoing film sequence. In the house, this is embodied in alternating between function-specific spaces such as living room, kitchen, etc. and the ramped or stepped links connecting them. We like to think that this gives the functional spaces as spaces of action, where the very configuration and equipment of the rooms compel one to go on with life and do with others the normal things that “one does.” On the other hand, the roofed ramps and stairs are spaces in which we might be compelled to slow down, to consider one’s life with a moment of reflection, realization of a sudden presence of doubt or encounter with a recurring indecision.
Study model of roof structure
How would you describe the architecture of Cerro Osa/Costa Rica and how does the building relate to it?

The desert and the jungle (as in this case) oppose the city as places characterized by an absence or scarcity of social, civic and cultural tradition. Architecture is one of those manifestations that, being a byproduct of dense human occupation, is rather scarce in this remote and wild place. In the void created by this lack of architectural tradition, buildings tend to assume forms that are largely dictated by the weather and other natural conditions. Our project relates to those building habits, as most buildings in the Osa Peninsula, by making very little use of windows, since temperatures year-round are pleasant enough not to have to enclose the space other than for insect protection. Other distinctive elements in local construction that are also present in our project are wide roof overhangs that protect the spaces from rain and excessive sun exposure and a consistent 30 cm step that separates the house from the surrounding landscape in order to prevent unpleasant visits from the many varieties of deadly poisonous snakes inhabiting these forests.

Email interview conducted by John Hill.
Study model of roof structure
Site plan
Ground floor plan
Roof structure details
Sections and elevations

Casa Osa

2013
Cerro Osa, Costa Rica

Client
Withheld

Architect
OBRA Architects
New York, NY, USA

Design Principals
Pablo Castro

Project Architect
Shin Kook Kang

Project Team
Atsushi Koizumi, Patricia Bohrer, David Karlin, Doreen Lam, Jennifer Lee, Edina Nathania

Structural Engineer
Robert Silman Associates

Contractor
Brad Shenko

Site Area
98 hectares (242 acres)

Building Area
375 sm (4,000 sf)

Photographs
Peter Lynch

Drawings
OBRA Architects

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