Casa Tobi by Espacio 18 Arquitectura is a study in contrasts, a house that finds its character in the tension between solidity and openness. The project, known as Harte Schale, weicher Kern (hard shell, soft core), sits on a steep site in Oaxaca where the Pacific coast meets rugged hillside.
From a distance the structure looks like a monolith, heavy with raw concrete, its surfaces textured in sandy tones that feel weathered by salt and wind. Step closer and the architecture begins to loosen, revealing circulation paths, courtyards and voids that soften the severity of its shell.
The topography dictated the form. Rather than cutting into the land to create a flat base, Espacio 18 allowed the house to descend in a series of staggered levels that fold into the terrain. This decision produces a building that feels inseparable from its site, as if it has grown from the slope itself. Arrival is unconventional. Visitors are drawn first to the rooftop terrace, where a reflecting pool mirrors the sky, before entering through a narrow passage that expands into generous interiors. The slow reveal heightens the drama of moving from a protective exterior into the light and air of the core.
The plan blurs distinctions between spaces. Living, dining, kitchen and work areas form a continuous flow, treated more like a landscape than a set of defined rooms. Espacio 18’s approach recalls Sou Fujimoto’s philosophy of interconnected environments where boundaries are porous and functions overlap. Large openings frame the ocean and bring the lush vegetation into view, dissolving the barrier between inside and outside. Concrete provides thermal mass for the heat of Oaxaca, its weight balanced by the openness of glazed walls and sliding partitions.
Water is a recurring theme, used as both structure and symbol. A rooftop pool reflects shifting skies, another stretches alongside the living areas as a social anchor, and narrow channels run along walls and steps, cooling the air and referencing the nearby natural waterfalls of Hierve el Agua. These elements extend the architecture beyond concrete and steel, introducing movement, reflection and sound into the daily rhythm of the house.
Private rooms are located deeper within the hillside. Here the mood shifts from panoramic exposure to calm enclosure. Windows frame selected views rather than opening entire walls, offering intimacy and focus. The contrast reinforces the central concept of the project: a tough exterior that conceals a softer, more contemplative heart.
Casa Tobi is not about spectacle. Its power comes from its restraint, its sensitivity to site and climate, and its ability to make material, water and light work together in balance. Espacio 18 Arquitectura has produced a dwelling that feels both timeless and deeply rooted, a building that protects yet embraces, that appears immovable yet breathes with its surroundings. It is a reminder that the best houses are not objects placed on a landscape but companions to it, shaping and shaped by the place they occupy. – Bill Tikos
Source: The Cool Hunter