An old, dirt road snakes its way through the 25-hectare forest in Grândola, not far from the Serra de Grândola nature reserve, a coastal mountain range covered with an abundance of cork oaks. Where the street leads over a sandy hill, the forest suddenly opens out and you find yourself in a clearing. And you are greeted by a rather incredible sight, a barkhan dune, which although quite typical to this region looks as if it has lost its way in the woods after having fled one of the Atlantic beaches close by. If, undeterred and in search of an answer as to what it is doing here, you carry right on up to the top of the mound you will surely find what you’re looking for. Because once you reach the top, you catch a glimpse of a wooden deck outside and a large pool area at the foot of the sandy hill. And slowly it all begins to make sense: you’re standing on top of a house!

The concrete building hidden beneath all this sand was erected by Lisbon-based Pereira Miguel Arquitectos in 2008. “Casa Monte” is its official name – but now people have come to refer to it with the simple and essentially appropriate name “The Dune House”.

Indeed, from your vantage point on top of the dune what you will still be unable to see are the house’s four arms, which are arranged in an x-shape beneath the mound of sand and divide the building up into four living areas each with its own distinct function. Its thick concrete walls are outfitted with large window fronts framed in wood, which ensure that the house’s interior receives sufficient daylight; the material is then continued as a theme on the outside with wooden decking in the terrace area. But the architects have gone beyond merely using natural materials to ensure that the building would visually blend with its surroundings. Other architectural details such as the warp-like roof, reminiscent of a wave it is destined to trace the organic contours of a natural dune, mean that the building blends in harmoniously with the landscape around it.

The idea of covering the construction with sand upon completion and in doing so create an artificial dune landscape in the middle of the forest was on the one hand inspired by aspects such as sustainability and well-balanced energy management. On the other hand, thanks to the natural clearing in the forest, there was no need for any extensive intervention in the natural surroundings. This is also the reason why the architects also opted to use the sand dug up from the actual construction pit to form the artificial dune, which incidentally led to a reduction in material and transportation costs too.

Given its geographical location, the Grândola area is constantly at the mercy of major fluctuations in temperature. Accordingly, the building’s thick concrete walls have been reinforced from the inside with redbrick cladding, while the sand and resulting vegetation also naturally serve to provide effective insulation and regulate the ambient temperature inside. Furthermore, most of the house’s windows face southward such that the building is flooded with maximum daylight as possible, even in the winter months. Whereas in the summer, wooden shutters keep out unwanted glare.

Alongside these key architectural aspects, the fundamental idea behind this building is extremely idealistic. In the “Dune House” the architects were aiming to create a living space where the boundaries between architecture and nature would be very much blurred. The house’s cave-like feel affords its occupants a feeling of safety and security when inside. At the same time, the “Dune House” constitutes a new habitat for flora and fauna, such that over time nature, weather conditions and flourishing vegetation, will mould and shape the house anew.

One particular statement made by the architects really drives home just how deeply their desire to create a true synthesis between architecture and nature is embedded at the very heart of their approach: “Maybe one day we’ll find a goat grazing on our roof, while we’re taking a dip in the pool below.”

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