An arced wall forms the back of this white concrete residence by architect Rafael Lorentz, which stands on a hilltop in the Brazilian countryside (+ slideshow).

HLM House sits atop a grassy hill on the outskirts of Santa Maria, a city in the country's southern-most state of Rio Grande do Sul.

Porto Alegre-based Rafael Lorentz selected white concrete for the building's structure, which was poured in-situ to create the curved wall at the rear.

A pair of straight walls were then set at right angles to the arc, to complete the house's skewed quadrant plan.

"From the beginning, the challenge found was how to build something that could rise in the landscape as if it had always belonged to the place," the architect told Dezeen.

"The house arises from a curve suggested by the site, embodied by a thick white concrete wall."

"The idea was to provide a place where one could find himself in deep contact with the landscape, near enough from the city so working was still possible," he added.

A row of slender concrete columns run across an opening at one end of the curving wall, which is dramatically uplit like an old folly or monument at night.

More of these concrete bars extend horizontally to form the canopy of a parking space that can also used for outdoor entertaining.

A black metal staircase spirals from a paved patio at the back of the house to a viewing platform on the building's flat roof. The roof is planted with greenery to help provide thermal insulation.

"Up there one can reach a quiet place to find yourself alone and just enjoy the beautiful view at east, made magical by everyday sunrise," said the architect.

Inside, the raw concrete walls are accompanied by warm-toned timber boards that line the floors and ceilings alike.

The majority of the space is divided up into two rooms, with a bedroom and bathroom at one end, and the kitchen and living room at the other. These two areas are separated by a narrow strip containing a toilet and utility rooms.

An arced breakfast bar made from concrete divides the kitchen from the main body of the living room. The low wall is made from concrete and features a pock-marked surface caused by air bubbles trapped during the casting process.

A second wall – this time full-height – curls from one corner of the bedroom to enclose a toilet, while a free-standing bath sits on the wooden floor at the end of the bed to take advantage of views down the valley below.

Large windows facing down the hillside open onto a slim concrete terrace that runs along the front of the property.

"Wide open windows allow the landscape to be a constant presence in everyday life," added the architect.

Photography is by Marcelo Donadussi.

Project credits:

Architect: Rafael Lorentz
Contractor: ICM Obras
Structural project: L2 Soluções Estruturais
Greenroof: Ecotelhado
Lightning: Ilumine
Windows: Rehau
Floor and ceiling: Barbieri Esquadrias
Bathroom devices: Laufen