Forest Blend

The roof is Laurent Troost Architectures’ contemporary interpretation of Brazilian colonial roofs, and several aspects distinguish it. For one thing, it’s metal, unlike Brazilian colonial roofs, which are often terra cotta or clay tiles. It has a clerestory section in the middle and gutters, which are not found on colonial roofs. Moreover, at two sides, steel panels continue from the roof into vertical shading panels, a feature found in modern Brazilian architecture in the form of concrete walls, but notable on Casa Campinarana for their formation in metal, says Laurent Troost, architect at the Manaus-based firm. These features and others throughout the project drew acclaim from the judges, which also noted the roof is integral to the project. Indeed, the roof on Casa Campinarana supports Laurent Troost Architectures’ overall design concept by blending with its forested surroundings and incorporating passive design elements.

One with the Forest

Physically and visually, the roof integrates the house with the surrounding forest, or Campinarana, the hardy region of the Amazon rainforest for which it is named. Physically, it is designed to function outdoors as well as indoors. The weathered steel panels continue on the underside of the roof assembly as soffit and ceiling panels. In another physical integration of the roof and forest, the northeast corner features an external skylight with an Açaí palm tree growing through it.

Visually, the reddish color of the Corten steel looks like clay soil on the property, and its mottled surface of flat-seamed, weathered steel resembles the texture of wood cladding, says Troost. Likewise, as the forest grows and changes, the Corten develops patina that changes colors.

“I wanted to achieve a warm, yet intriguing, atmosphere, almost like a wooden cladding,” Troost says. “The choice of Corten as roof material was due to its low maintenance and evolutionary character in harmony with the forest of Campinarana and its reddish clay soil so present in the landscapes of the Amazon.”

Positioned for Shading

In addition to focusing on the forest, special attention was given to energy use and passive design. “[The overall design concept was] to create an architecture integrated with nature in all aspects, visually speaking, but also in terms of impacts [including] small footprint, small energy needs, etc.,” Troost says.

In terms of passive design elements, Casa Campinarana features many including five main ones, most in which the roof plays a direct role. First, the building is oriented to minimize solar heat gain. It is massed in two rectangular volumes, one running north/south, traversed in its northern half by the other volume running east/west, which is covered by the roof. The north/south volume is thin and, because it is not completely covered by the roof, contains spaces that don’t need complete protection from the elements including a pool, entrance, garage, storage room, laundry room and room for watching television. The east/west volume is wider than the north/south volume, and fully protects spaces from weather including the kitchen, dining room, bedrooms and living room.

A second passive design element is on the house’s east/west volume. Vertical shading panels of weathered steel continue from the roof and protect living spaces from sunshine as the sun rises and sets at the east and west sides. In a third example, at the north and south sides of the east/west volume, 2-meter-wide eaves shade sunshine from living spaces.

Airflow and a Flip-Flopped Floor Plan

The fourth main passive design element, facilitating and controlling cross ventilation throughout the house, is accomplished, in part, through the roof and its clerestory section, sliding glass walls, glass fins, and, in a fifth passive design element, the building’s thin footprint.

For ventilation and connections between indoor and outdoor spaces, the clerestory allows airflow, and movable glass walls on the second floor open the kitchen, dining room and living room to the outdoors. Spaces covered by the roof that remain outdoors when the sliding glass walls are closed include a terrace, barbeque area, shower stall and bathroom. To control wind at the north side, where most of it is directed, Laurent Troost Architectures added glass fins at the second floor.

In addition to promoting ventilation, a thin footprint aligned with the overall project goal to blend the house with its natural surroundings with minimal environmental impact. To create the thin footprint, Laurent Troost Architectures flip-flopped the rooms typically located on the first and second floors of a house. In Casa Campinarana, bedrooms are on the first floor, and the main living spaces are on the second floor.

“Switching floors helped to reduce the footprint because in a normal configuration, all of the external functions from the current upper floor such as the pool, deck, barbeque area, shower, etc., would need to occupy an area used by the Campinarana, and, therefore, we would have had to cut down many trees and increase the building footprint,” Troost says.

Construction Details

In terms of construction, structurally, Casa Campinarana has a concrete structure ground floor and structural steel second floor. The roof is supported by eight V-shaped steel columns that are attached to the lateral sides of concrete beams.

The roof assembly has four layers. From outside to inside, there is a 2-mm-thick SAC40 Corten steel sheet, 1-inch-thick steel profiles to structure the steel sheets and 4 centimeters of air, 15 centimeters of high density expanded polystyrene (EPS) foam insulation, and a 2-mm-thick SAC40 Corten steel sheet. Evano Sousa de Lima, of Manaus, installed and welded 6,200 square feet, in 80 sheets, of the Corten steel, which was supplied by Gerdau SA in Manaus.