Many architects claim they build with light, as if they possess an alchemical ability to make the ethereal material. With his Bahia House, the S'o Paulo'based architect Marcio Kogan, of Studio MK27, does them one better: He builds with breeze. Combining the principles of contemporary design, traditional Bahian siting, and vernacular materials, Kogan produced a fantastically efficient house that seems to breathe with its environment.

Bahia, a state in the northeast part of the country, is essential Brazil ' home to many of the country's cultural icons: samba, capoeira (a martial arts'related dance), and candombl' (the Afro-Brazilian religion). It is a place where Brazil's colonial past, its history of African slavery, and its native traditions come together in a soulful, languid mix, typified by the extremely laid-back nature of the Bahians. The climate is hot and humid year-round.

Approached by going up a steep hill, in a gated residential neighborhood of the state capital, Salvador, the house, finished by Kogan in 2010, has a square plan built around an open-air courtyard. Three sides of the square are constructed in natural stone, or moledos. The fourth side, which faces the street, is an open volume framed by the overhanging roof that rests atop the opposing stone walls, and by a simple floor-to-ceiling mashrabiya (an Arabic screen) extending the 67-foot-long elevation. The screens can be folded in accordion fashion to reveal a second layer of 8-foot, 10-inch-high glass panels, which also slide completely out of the way. This design feature means the living/dining space can be entirely open from the street to the courtyard and beyond to the bedrooms contained in the wing on the opposite side. Except for eight wood-clad square concrete columns, the space is unimpeded, allowing cross ventilation to take full advantage of the prevailing winds from the nearby Atlantic Ocean.

The house, however, is not by the sea. It sits in a lush, densely forested setting, immediately adjacent to the city's zoo. As a clue to the house's seamless integration with the natural surroundings, the little sagui monkeys from the zoo are frequent guests, attracted most likely by the three giant mango trees, each over 100 years old, which provide a natural canopy to the property's open spaces.

The owner initially tried to hire Kogan to renovate an existing structure when he bought the site. Kogan declined the offer. 'The house was hideous, plus it had bad energy,' he recalls. After a series of unappealing renovation proposals from other architects, the owner came back to Kogan and agreed to start from scratch. The mango trees are all that remain. And with two of the three essentially centered on the lot, they helped Kogan to define the shape of the house: 'I like single-story houses best,' he says. 'And since the lot was big enough, we could create the square patio inside, which is a typical Bahian reference.'

For three sides of the square, interior walls define the nonsocial spaces ' kitchen and service areas, bedrooms and bathrooms, and a den and home office, respectively. A mashrabiya along the back courtyard wall screens the bedrooms from the linear swimming pool edging this wing to allow a similar blurring of indoor and outdoor spaces. But Kogan's real mastery is in transforming the stone walls from traditionally imposing enclosures to delicate dividers of space ' nearly equivalent to a sliding glass panel, or folding mashrabiya ' which invite the interior and exterior landscapes to mingle. The floors of these three sides of the plan are all 15 inches below grade. In Kogan's words, 'We sunk the house.' From inside, the subtle shift in scale allows the surrounding forest to appear to bleed over the walls and into the interior courtyard.

To accentuate the effect, the first course of stones in each wall are laid flush to the ground, creating the illusion that these portions of the house might still be sinking slowly into the earth. The stones vary in size, but were all selected to be nearly rectangular. As a result, strong horizontal lines are generated that, together with the planarity of the roof line, create a Modernist reference in harmony, not in conflict, with the rustic material.

For the ceiling in the living and dining space, Kogan performs a similar trick with wood that the owner had collected from building demolitions. By rip-cutting every piece to the same narrow width (but leaving them with varied lengths), the ceiling projects a linearity that exaggerates the span, while each board, left otherwise unfinished, retains its individual character ' a modern patchwork in wood.

Through attentive, subtle detailing, Kogan gets rustic materials to perform, without a hint of contradiction, in an explicitly Modern context. A stark example is the clay-tiled roof over the front side of the house. Almost every neighbor in the community uses the same roofing material, the ubiquitous symbol of Brazil's colonial architecture. But Kogan points out that the clay tiles are emblematic precisely because they are appropriate to the climate. Despite Salvador's constant sticky weather, the living area in Bahia House contains no air-conditioning at all, not even ceiling fans. Together with the well-thought-out positioning of the house, the tiles create perfect thermal efficiency.

Sitting in the house's living room in classic Brazilian Mole chairs designed by Sergio Rodrigues, with all the mashrabiyas folded shut but the glass panels left open, one feels the cool breeze invading the space. The mango trees shade the hot summer sun. The ambience, even inside, is of a lazy veranda. Time slows to a Bahian pace. There is a Bahian custom, to varandar ' to take a leisurely stroll along the beach, stopping at each and every house's veranda to chat with neighbors. Such a verb could have been created only in Bahia, as Kogan's house superbly demonstrates.

Completion Date: January, 2010

Gross square footage: 7,420 sq.ft.