Estudio Feller Herc Sets a Board-Formed Concrete Family House into the Dunes Outside Colonia del Sacramento

On the sandy outskirts of Colonia del Sacramento, where rough scrub runs down toward the Río de la Plata, Estudio Feller Herc, the practice of Carolina Feller and Melisa Herc, completed La Flecha in 2017. It is a 360 m² house for a family whose children have grown up and moved on. The brief was about getting everyone back under one roof: a place for reunions, long meals and shared summers rather than a set of private retreats.

What makes the house worth your attention is how much it asks of one material. Board-formed concrete does nearly everything here. It is heavy enclosure, open pergola, perforated screen and roof edge for a strip of planting. The architects used a deliberately limited palette and then worked hard to make the concrete porous, so light, air and landscape pass through it. The result is a heavy house that does not feel sealed off from the dunes around it.

A Concrete Mass That Sits Low in the Scrub

From a distance, La Flecha reads as a long, low body of board-marked concrete with a single two-storey volume rising at one end. The ground floor is largely glazed, so the upper mass seems to hover over a band of glass and shadow. Against the dune scrub and the big Uruguayan sky, the grain of the timber formwork does useful work. It gives the grey surfaces a texture close to the weathered wood and dry grasses around them.

The street side is tougher. A deep carport overhang and a ribbed screen give the approach a sense of protection. Solar heaters sit openly on the roof, and nobody has tried to hide them. We like that honesty. In a house this committed to raw material, a cosmetic parapet over the equipment would have rung false.

Pergolas as Light Instruments

The architects describe concrete used in two ways: as perforated mass and as linear elements. The pergolas are the clearest version of the second. Deep concrete beams run out past the glass line and frame the sky in strips. Through the day they cast moving bands of shadow on walls and floors. This is how the house delivers on its claim to change with the sun. The effect comes from section and spacing, not from added shading devices.

At dusk the logic flips. The glazed ground floor glows from inside, the beams turn to silhouette, and the chimney flues read as small vertical markers against a purple sky. A red aloe in bloom at the foot of the frame is a small detail, but it shows the planting strategy: hardy, local and left fairly wild.

Thresholds, Courtyards and Gravel

The entrance is modest: a tall timber door set into board-marked walls, with grasses spilling over the roof edge above. That green fringe matters. It softens the top line of the concrete and suggests the roof is part of the ground it sits on, not a lid over it.

Inside, a gravel courtyard planted with potted agaves and cacti breaks up the plan and brings in light from above. The concrete-floored corridor beside it picks up long streaks of sun, and the cross ventilation the architects describe works through openings like this one. The planting is sparse and drought-tolerant. It is the dune landscape edited, not replaced with a lawn.

A Stair That Barely Touches the Wall

The stair to the upper volume is one of the most refined moves in the house. Timber treads cantilever from a board-marked wall, with no stringer and no visible support, and recessed niches cut into the concrete beside them. Reflected in the long glass wall of the gallery, the treads seem to float twice. Warm timber against the cool concrete is an old pairing, but here it is carried out with real restraint.

One Room for the Whole Family

The core of the program is a single large public space. It combines living area, kitchen, parrilla, pergola and outdoor extension. The kitchen island sits under a skylight cut straight into the concrete ceiling, so whoever is cooking stands under a shaft of daylight. Floor-to-ceiling glazing faces the dry planted landscape. The architects frame three views from this room: the river to the south, open countryside to the north through a large window, and the sky through the lucarna.

This is a plan built around a long plank table, not a sofa. For a family that now comes together on occasions rather than every day, that priority makes sense. The house is set up for cooking, eating and lingering together.

Outdoor Rooms Under Concrete Beams

The covered terraces show the interior-exterior blur the architects were after. A long timber dining table with benches sits under the concrete pergola, half shaded and half open. Tall grass presses right up to the edge of the deck. There is no manicured buffer between house and landscape, which keeps the rustic, stripped-back character the brief asked to protect.

The Roof as a Second Landscape

Climb up and the roof becomes a terrace of its own. A timber deck with a bench and low table sits among tall grasses, with black vent stacks and a distant waterline beyond. From the upper deck, under a slab fringed with vertical concrete fins, you look down onto a glass-railed lap pool and out across the coastal scrub.

The pool placement is a practical decision with a spatial payoff. It sits as close to the house as possible, positioned so it casts no shadow on the house in summer. That keeps the water within reach of the living spaces without compromising the home's light.

Bedrooms Kept Simple

The private rooms are quieter, as they should be. One bedroom pairs the bed with a vertical timber slat partition, a built-in shelf and a small ledge, using timber here to filter rather than enclose. Another has a freestanding steel fireplace above a concrete bench with stacked logs, and glass sliders open straight onto a deck. A fire in the bedroom of a summer house is a sensible idea on the Río de la Plata, where shoulder-season nights turn cold.

Plans and Drawings

The drawings explain the massing. On the ground floor, a long wing holds the open living and kitchen space and three bedroom suites, with a long pool and a paved parking court alongside. Upstairs, a single bedroom volume with its own bathroom sits alone on the roof terrace, surrounded by planting. The sections show the house stepping down a gently sloping site, with the pool sunk into the ground and the grill hearth expressed as its own chimney flue. The parrilla is treated as a fixed element of the architecture, not an appliance.

Why This Project Matters

Coastal houses in the Río de la Plata region often go one of two ways: lightweight timber pavilions, or sealed concrete boxes with big windows. La Flecha takes a third path. It shows that board-formed concrete, handled through pergolas, perforations, fins and handmade precast elements made by local craftspeople, can be as porous as a timber frame while giving the thermal mass and durability a windswept, sandy site needs.

It also offers a clear model for the multigenerational holiday house. Rather than spreading out into many private wings, Estudio Feller Herc put most of the effort into one shared room and its outdoor extensions. The bedrooms stay modest, and the generosity goes to the table, the grill and the views. For a family coming back together, that is the right place to spend it.

La Flecha by Estudio Feller Herc (Carolina Feller and Melisa Herc), Colonia del Sacramento, Uruguay. Area: 360 m². Year: 2017. Photography: Analia Grucki.

About the Studio

Estudio Feller Herc

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