ARCA, an arched retreat in the Brazilian rainforest | Atelier Marko Brajovic

November 4, 2015

The humid forest of Brazil’s Costa Verde is the setting for this unusual small house. Nicknamed “Arca” (“Ark”) by the locals for its resemblance to an overturned vessel, the arched house was built as a getaway by architect Marko Brajovic. He designed it as a place where small groups could go to relax or to work while inspired by nature.

Wanting to minimize site disturbance, the architect started with a prefabricated metal building typically used for storage or industrial purposes. This particular building was designed to be assembled by hand, and it took only a week to complete the shell on the concrete pier foundation.

As the shell is entirely self-supporting, there are no support columns to impose constraints on the interior layout. In addition, since the end walls are non-structural, the architect could fully glaze both ends with a grid of aluminum-framed windows and sliding doors.

To warm up the industrial look, Eucalyptus boards were used for all the interior walls. Two bedrooms and bathroom facilities are partitioned off along the sides of the 72.6 m² (781 ft²) floor plan. The “roofs” of these side rooms could potentially be used as sleeping lofts as well. The center was left as an open living and work space with a ceiling nearly 5 m (16′) high. When the house is being used for a working retreat, the beds fold up into couches so the bedrooms can become office spaces or breakout rooms.

A-frames, arched buildings and similar structures where the roof comes down to the ground on both sides often suffer from a cave or tunnel effect from having large windows on the ends and few if any on the sides. Here the architect avoided that by keeping the end-to-end distance shorter than the width. It would be cheaper to get the same floor area in a shell that is longer and narrower, due to the reduced span, but that wouldn’t make for as livable a home.

The building doesn’t appear to have insulation, however the manufacturer claims that the Galvalume panels are very effective at reflecting the sun’s heat. The floor is raised above the ground, allowing breezes to flow both under and through the house. A pair of wind-driven roof turbine vents also pull out hot air.