OMCM arquitectos Builds a Summer House in Paraguay from Quarry Waste Blocks and Three Sacred Trees

The name tells you what matters most. Yvyraju is the Paraguayan name for Albizia hassleri, a native tree species, and three of them stood at the center of this site in Altos before anything was designed. OMCM arquitectos, led by Matias Ortiz and Maria Paz Chamorro, made the decision not to clear them but to organize the entire house around their trunks. The result is a 696-square-meter summer residence that reads as a single lifted bar, 12 by 24 meters, hovering on six concrete pillars while a courtyard punched through its center lets the trees grow uninterrupted into a rooftop garden.

What makes the project worth studying goes beyond preservation sentimentality. The studio manufactured its own construction blocks on site, using residual stone from local quarries that would otherwise end up as waste. The walls are only five centimeters thick, incorporating air chambers for thermal mass. It is a genuine circular economy experiment dressed up as a family vacation house, and the roughness of the material is not apologized for but treated as the defining aesthetic.

A Lifted Volume on a Sloping Site

From the street, the house presents itself as a horizontal slab of concrete and stone, cantilevered at the edges and supported by pillars clad in the same quarry-waste blocks. The decision to elevate the main volume does two things simultaneously: it handles the site's natural slope without excessive earthwork, and it allows the ground plane to remain open, letting lawn and vegetation flow beneath the structure. The approach recalls a Corbusian pilotis strategy, but the materiality is unmistakably Paraguayan. There is nothing white or sleek about it.

The street-facing facade is deliberately closed, a response to a developing neighborhood where privacy is needed but complete introversion would be oppressive. Timber louvers and deep-set openings punctuate the stone surface, giving the house a defensive posture from the public side while the interior opens aggressively toward the courtyard and garden.

The Courtyard as Cloister

The central void is the spatial engine of the house. Three Yvyraju trees rise from stone-lined beds through the open center, their white bark catching sunlight and reflecting it back into the surrounding glazed corridors. Steel and glass bridges span the gap at the upper level, connecting social spaces on one side to bedrooms on the other. The arrangement borrows from the cloister typology: a covered walk surrounds an open garden, and every room in the house draws its light and air from this single source.

What elevates this beyond a standard courtyard plan is the vertical continuity. The trees don't stop at the roof. They grow up through the rooftop terrace, making the fifth facade as green and inhabited as the ground level. It collapses the hierarchy between roof, garden, and interior in a way that feels both effortless and carefully calculated.

Circulation Through Stone and Light

Moving through the house means moving through changes of material and light intensity. A stone staircase descends through the courtyard under a steel and glass pergola, dappled shadows shifting across the treads as the trees filter direct sun. Inside, an open steel stair rises between stone walls with the courtyard always visible below. The corridors at the upper level are fully glazed on the courtyard side, with concrete soffits overhead and leaf-shadow playing across the floor.

The effect is processional without being grand. There is no monumental entrance or double-height foyer. Instead, the house uses its split levels and the slope of the terrain to create a continuous sequence of compressions and releases. You descend into the garden, ascend past the trees, and arrive on the roof with a view back down through the canopy.

Interiors of Concrete, Stone, and Timber

Inside, the palette stays honest: exposed concrete ceilings, quarry-stone block walls, timber door panels, and black steel framing. The kitchen features a stone wall with a small deep-set window and a wooden range hood, a detail that feels more domestic workshop than luxury summer house. The living spaces open fully to the garden through floor-to-ceiling glass, collapsing the boundary between inside and out.

The five-centimeter wall thickness is remarkable for a masonry construction. OMCM arquitectos achieved this by building air chambers into the block assembly, which serve double duty as insulation. The resulting surfaces have an unfinished, almost brutalist quality, but the warmth of the stone color keeps the interiors from feeling cold. Light enters in controlled doses: through the courtyard, through narrow window slots, through glazed bridges overhead.

Pool, Terrace, and the Fifth Facade

The program is, after all, a summer house, and the outdoor spaces earn their weight. A rectangular pool sits on the garden side, shaded by a white steel pergola and framed by the cantilevered volume above. The covered terrace with limestone pavers provides a generous outdoor living room, its proportions generous enough for the kind of extended family gatherings the brief called for.

From the garden, the house reads as a series of horizontal layers: stone base, concrete slab, timber louvers, planted roof. The flowering shrubs and palms in the foreground soften what is otherwise a very muscular composition. The tension between the heavy materiality and the lightness of the lift is the building's most compelling formal quality.

Rooftop Garden and Solar Infrastructure

The roof is not an afterthought. Timber decking, steel railings, planted beds, and skylight openings around the tree trunks make it a fully inhabited level. The aerial views reveal the extent of the operation: solar panels occupy a substantial grid on one portion of the roof while garden beds and timber terraces fill the rest. The trees that justified the courtyard void now provide canopy shade for the rooftop, completing a cycle that began with refusing to cut them down.

The integration of photovoltaic panels alongside productive garden beds on the same roof is a practical statement about what sustainability looks like in a subtropical Paraguayan context. It is not a showcase technology; it is simply part of the house's metabolic system, alongside the air-chamber walls and the site-manufactured blocks.

Plans and Drawings

The floor plans confirm the clarity of the parti: a rectangular bar with a courtyard subtracted from its center, social spaces on one side, private rooms on the other, and the pool terrace extending the footprint to the east. The longitudinal section reveals how the split levels negotiate the sloping terrain, with the elevated volume creating a covered ground-floor zone for services and guest quarters. The transverse section shows the two-story volume floating on its columns, the tree canopy rising above the roof line.

Particularly telling is the construction detail drawing, which lays bare the foundation, column base, floor slab assembly, and paving system. This is where the five-centimeter wall and air-chamber technology become legible, and where the project's ambition as a constructive laboratory is most evident. The physical model, photographed against a black background, strips the house down to its essential proposition: a horizontal volume on pilotis with three trees punching through.

Why This Project Matters

Yvyraju House treats a summer residence as a testing ground for ideas that matter well beyond its program. Manufacturing construction blocks from quarry waste on the building site itself is not a symbolic gesture; it is a replicable technique that competes with conventional market materials on cost. The five-centimeter wall with integrated air chambers challenges assumptions about what masonry can do in a subtropical climate. And the refusal to remove three native trees, turning them instead into the organizational principle of the entire plan, demonstrates a design methodology that starts with what is already there rather than with a blank slate.

OMCM arquitectos have described the house as a laboratory, and the word fits. Laboratories are not pristine; they are places where things are tried, where imperfection is accepted, where results matter more than polish. The rough texture of the blocks, the visible steel bracing, the exposed construction logic: all of this reads as confidence rather than carelessness. In a region where contemporary architecture too often defaults to imported finishes and global aesthetics, this house argues persuasively for a different path, one grounded in local materials, local trees, and local intelligence.

Yvyraju House by OMCM arquitectos (Matias Ortiz and Maria Paz Chamorro). Located in Altos, Cordillera, Paraguay. 696 m². Completed 2022. Photography by Leonardo Méndez.

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