A house for Olga: living beside the Guadiana in a former smuggling watchtower

Sanlúcar de Guadiana is a place you arrive at by water. The Guadiana river, in this border stretch between Spain and Portugal, traces broad meanders between hills covered in scrubland, holm oaks and eucalyptus, before opening towards the Atlantic. Sailing boats that travel up the estuary from the sea find their first river shelter here: a small village perched on the hillside, with free anchorage and a community of sailors who arrive, stay for long periods and, more often than not, stay for good. A large part of the population is foreign —mainly British— and the village has spent decades accumulating that quality of a place one arrives at by chance and ends up never leaving. This open identity, bound to travel and water, made of departures and returns, of temporary lives that become permanent, is the backdrop of Piedra y Agua..

A ruin by the river

Olga arrived in Sanlúcar the way almost everyone does, by boat, passing through, as a refuge between crossings. First in scattered stays, then sharing a cabin by the river, later acquiring a ruin together with her partner at the time —an Argentine sailor and artist— with the idea of building a shelter of their own between voyage and voyage. What began as a place to return to ended up becoming the only place to return to, home.

The ruin they chose was no ordinary ruin. On the hill on the left bank of the river, on Camino del Romerano, stood the remains of a former Civil Guard border post, built in the late nineteenth century to monitor smuggling between Spain and Portugal. The stone masonry walls, with their loopholes still visible beneath the window openings, had survived abandonment with the solidity of something built to endure, to watch the river, to remain.

The architect Manuel Silva Zurita had known that place since childhood. A friend of Olga’s son, he had spent time in Sanlúcar and along the Guadiana with that family for years. Piedra y Agua would be his first built project as an independent architect. Simone Lorenzon and Valeria Polato, of Kalibra Arquitectura, collaborated with him on what would also be the first joint project of both studios.

Inhabiting a ruin

The first decision was the most important one, not to restore the ruin as a historical object but to inhabit it. To use the existing stone perimeter as a structural and spatial element —the geometry that defines the thresholds, the atmosphere, the scale of the life that is going to unfold inside. This compact construction, which consolidates what was already there, adds only a discreet extension.

From the outside, the house reads as a layered continuity. The original whitewashed masonry below, the new white render above, the line between them exposed without concealment. The roof slopes in the opposite direction to the hillside —hiding from the access road, protecting privacy— and rises towards the river to open a single opening that frames the fluvial landscape. A single gesture, a single view, the Guadiana seen from inside what was once a watchtower.

An interior without doors

The interior is conceived as a continuous sequence. There are no doors; privacy arises from the thickness of the walls, the alignment of the openings, the interior view of each space. This decision —which in another house might be a formal whim— has a reason here, Olga lives alone in the middle of the countryside and feeling protected is essential for her. At the same time, the house needs to be able to open up to family, to friends, to impromptu gatherings when the river brings visitors.

The space thus unfolds as a single flexible setting: intimacy without isolation, openness without exposure. The journey through the house extends the paths that cross the fields towards the water, as if entering were simply to keep walking, to find the place to stop.

The bedroom is in the mezzanine, a pine wood platform suspended above the main volume and flanked by a large library. A large wooden window opens out towards the river; beside it, two armchairs to enjoy the water close at hand and books, always within reach, to travel beyond the ocean.

Economy and matter

With a tight budget and a site of difficult access, the project is built from an economy of means in which reuse is the working method. The small stove, a found old cupboard, the appliances, the fireplace, leftovers from other works. The same roof beams are used to build the staircase and parts of the kitchen; the same material as the continuous cement floor resolves the countertops, showers and basins. The porch —a minimal galvanised steel structure covered with reeds— changes its shading surface according to the season and whatever is available.

Beyond aesthetics, the continuity of materials is the logic of a house built with what is at hand, one that accepts what is found and integrates it without forcing it. An old cupboard rests against a stone wall a hundred and fifty years old. A rush lamp hangs from the pine ceiling. The Argentine artist’s paintings inhabit the lime-washed walls. Nothing is out of place because the place itself holds the memory of different times.

The house’s climatic strategies follow the same logic: thermal mass, cross ventilation, orientation. The stone walls store coolness overnight and release it during the day. The double height stratifies warm air upwards. The roof is oriented to avoid afternoon sun. There is no air conditioning. Energy comes from a photovoltaic system installed in a nearby structure that also serves as shaded parking.

Living in the south, differently

This project distils a chosen position on how to inhabit the south, as physical experience rather than image, as sincere acceptance of heat, shadow and matter that ages. Against the houses that opt for over-air-conditioned spaces detached from their surroundings, this house proposes something simpler and more demanding at the same time, a way of life less spectacular and more present.

The river keeps flowing. The sailing boats keep anchoring. Olga lives on the hill, in the house she chose, the one that was a watchtower and is now her refuge. The stone is the same as always. The water too.

Project: Piedra y Agua.
Location: Camino del Romerano, Sanlúcar de Guadiana, Huelva.
Area: built 91,50 m² /usable: 76 m².
Completed: 2025.
Authors: Manuel Silva Zurita. Zurita Studio; Simone Lorenzon, Valeria Polato. Kalibra Arquitectura.
Studios: Zurita Studio + Kalibra Arquitectura
Contractor: Pedro Madrid.
Photography: Juanca Lagares. Ulrich Stockhaus.
Awards: VI Premios COAS Arquitectura & Sociedad 2025.
Premio Arquitectura y Preexistencia, categoría Uso Residencial.
Source: Linka News.

Manuel Silva Zurita

Manuel Silva Zurita graduated with honours from the School of Architecture at the University of Seville. Before opening his own studio, he spent three years working in Switzerland —in Zurich and Lucerne, at Masswerk Architekten and Marques Architekten— in an environment where constructive precision, rigour in detail and clarity in decision-making are conditions of work. That period still shapes his approach to architecture today: projects that are coherent with their place, built from precise ideas.

In 2021 he returned to Seville and founded Zurita Studio. From there he works primarily in bespoke residential architecture, with particular attention to healthy spaces and climate efficiency. The connection with Switzerland remains active through his collaboration with architect Ulrich Stockhaus on projects in both countries, an exchange that interweaves different building cultures and climatic conditions.

The relationship with the client holds a central place in his practice. Each commission represents a world of its own —a way of living, a set of priorities, a place— that demands careful reading before any architectural response. This sustained method earned him the COAS Award for Residential Rehabilitation for Piedra y Agua, a project also recognised in the International Category of the COAS Architecture Awards alongside Kalibra Arquitectura.

He is also a member of the Governing Board of the Official College of Architects of Seville as Representative for Young Architects, participating in contemporary professional debate and in the development of sound criteria for architecture in the Andalusian context.

Kalibra Arquitectura

Kalibra Arquitectura was founded in 2021 by Simone Lorenzon and Valeria Polato, architects whose careers were shaped largely at Nieto Sobejano Arquitectos, a leading Madrid practice where they worked together for years on cultural and public projects of European scale. The studio operates from Madrid and Padova, developing projects primarily in Spain and Italy.

Lorenzon, trained at the Politecnico di Milano and with a master’s degree from the Universitat Politècnica de Catalunya, worked as lead architect on projects of high technical complexity, including the competition for the Cité du Théâtre in Paris and a sports and cultural centre in Reignier-Esery, France. Polato, a graduate of the Università Iuav di Venezia with a specialisation in digital architecture, has been associated with Nieto Sobejano’s work for over a decade, collaborating on international competitions and projects of varying scale.

The studio’s name condenses its position: kalibra denotes the balance they seek in every project between design quality, environmental responsibility, and the specific conditions of each client and place. That balance is built as the outcome of a process of dialogue — with the landscape, the materials, the cultural context — that begins at the first encounter with a commission and holds through to the final detail.

Despite its short track record, Kalibra has already received two awards from the Official College of Architects of Seville: for Martina y Madrid and for Piedra y Agua. The studio integrates advanced digital tools across all phases of the process, as part of a method grounded in precision and design rigour.

Project by Manuel Silva Zurita