The house is located in Los Reartes, a tourist resort in the Calamuchita Valley, at an altitude of 800 metres. It is part of a growing residential area overlooking the Barranco de los Molinos reservoir. The reinterpretation of vernacular architecture is evident in the stone walls and light wooden and sheet metal roofs.

The built volume on the 10 x 30 metre plot is arranged in longitudinal strips, with the services, living area and carport on the ground floor and the bedrooms inserted perpendicularly on the upper level. Two metal modules topped by light corrugated sheet metal roofs punctuate the composition to the north and house the living spaces, which open onto the patio. To the south, a hand-cast, exposed concrete tower introduces a sculptural element, breaking the symmetry of the layout.

The material takes centre stage: the reinforced concrete is 'pitted' with stones embedded in the cast, altering its regularity and breaking up the horizontal pattern left by the wooden formwork. The surface of the cast is sometimes smooth and sometimes rough, and coexists with sheet metal painted in pastel shades that echo the tones of the local rocks. Even the entrance handle, formed from four white Micosa stones, adds a poetic touch that is rooted in the context. The materiality of the concrete is also reflected in the staircase: the first steps emerge directly from the ground and transform into a light, suspended structure made of folded white sheet metal.

Thin ribbon windows accentuate the interpenetration between inside and outside by creating cuts of light between the walls and ceilings. However, it is the irregular opening that characterises the tower and breaks its compactness that catches the eye, offering a view of the surrounding landscape. At the rear, a terrace carved out of the upper floor looks out onto the garden.

The house, designed for occasional use, is equipped with a system of movable enclosures that regulate its opening and define an intermediate space. When closed – as it is for most of the year – it appears as an enigmatic volume, rigorous in its formal synthesis. But once open, it transforms into a machine à habiter permeable to light and environment.

Inside, the systems run exposed in metal pipes, declaring the building's constructive honesty. The kitchen countertop is made of reinforced concrete, with a shelf carved from a roughly hewn tree trunk. Details such as rattan chandeliers pay homage to Argentine tradition.

The entire project rests on a tension between opposites: between the heaviness of the tower and the lightness of the metal modules, between the roughness of the stone and the softness of the corrugated sheet metal, between the essentiality of the layout and the refinement of certain details. A stone suspended on the terrace, the line of light separating the surfaces and the possibility of modulating the entry of light transform Casa Lelis into a sensitive and changeable architectural device.