by Bruno Stagno

The sun is one of the most abundant resources in the tropics, and diverse technologies already harness its energy successfully. However, as a design determinant, it is not sun but shade that is a fundamental element of architecture in tropical latitudes. Here, shade summons and generally conditions behavior. Just as sunlight and its warmth are invigorating in cold climates, in the tropics it is the coolness of shade that allows people to be active.

In hot, dry regions like North Africa, closed spaces with thick walls and few apertures keep interiors cool. The contrast of light and shade and the spatial relation between the interior and the exterior are dramatically expressed in the thickness of these walls.

Just as the architecture in dry climates is of walls, in the tropics it is of roofs. The tropical roof is a parasol; its overhang extends to provide protection from the sun and the rain. Because it reduces lethargy and promotes well-being, shade becomes an important source of "passive energy."

One's well-being further depends on ventilation to lower the effective temperature and humidity. So in tropical architecture, walls are minimized and their openings enlarged to allow the breeze to move through without hindrance.

Open spaces covered by large roofs create an interesting aesthetic mix of shade and diffuse light. Inhabiting these buildings are the depth, the reflections, the veils, the chiaroscuros, and an attenuated clarity that are created by the shade. The shadows made by eaves, pergolas, and other elements produce a transition between the intense light of the exterior and the deep shade of the interior. One perceives that the interior shade is surrounded by perimeter half shades.

This partial-shade perimeter has depth and width, and it suggests a universe of light, shadow, and experiences. Resolving this transition between inside and outside can become an important theme of design. Furthermore, the transition is an opportunity to characterize tropical architecture beyond the traditional umbrella and convert it into a truly architectural entity. It is in this space where the building is refreshed, where the light is subdued, where shade invades the apertures, and where the breeze improves ventilation.

In these half-shade perimeters, a baroque game of transparency and ambiguity predominates. Thus shade, both as necessity and as poetry, is a strategic design resource. Together with ventilation, roofs, eaves, and vegetation, shade gives tropical architecture its cultural identity and character.

Bruno Stagno, is a Chilean-born architect who practices in San Jose, Costa Rica. He is the founding director of the Institute for Tropical Architecture and author of "An Architect in the Tropics." This article is an excerpt from a paper he presented at the UIA conference in Berlin, July, 2002.

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A "green screen" wrapping the J & R office building creates a shaded microclimate on the north and south facades, reducing direct sun on the glass without darkening the interior. The east and west faces are closed. Photo: Bruno Stagno The Bank of San Jose-Rohrmoser branch is shaded by a floating roof of scales over a three-dimensional frame, admitting light through controlled openings. A large central gutter emphasizes the north-south axis of the roof. Image: Bruno Stagno Visors were designed for the Credomatic call center so that sunrays never hit the facades. The bioclimatic design is enhanced by climbing plants. Image: Bruno Stagno The low-cost Pergola office building is a precast concrete structure covered by curtain walls. Vertical pergolas shade the facades, moderating the microclimate in front of the glass. Image: Bruno Stagno   Click on thumbnail images to view full-size pictures.