Edith Minkner in conversation with Anna Tarragona and Lars Höhne

EM: In Mallorca, many of the finest plots are on slopes, offering magnificent views. For architects, this is certainly a challenge. What needs to be considered when designing on one of these beautiful but steep sites?

AT: It is always crucial to understand the site and its potential in order to achieve the perfect concept and an optimal realisation. With sloping plots, specific aspects come into focus, such as the terrain, the orientation of views and sunlight, access solutions, and of course the planning regulations.

EM: What are the planning requirements for sloping plots?

LH: Every municipality interprets the rules a little differently, often depending on the slope and on the planning history of the site. The decisive factor is always the so-called “terreno de referencia” – the officially recognised ground level from which all height limits are measured. In Palma this is usually the original, natural ground, while in Calvià it may be the survey that was carried out when the masterplan was approved. These reference levels must always be checked against a current topographical survey, and any discrepancies clarified with the municipality before design work begins. Only then can you know, for example, how far the ground floor may project above the slope, how terraces or pools may be integrated, or to what extent outdoor areas can be terraced. A precise definition of the terreno de referencia is therefore the foundation for every successful project on sloping land.

AT: This is why our work always begins with creating a 3D terrain model, which we use in every stage of the process to optimise the project. From the outset we can check in the model how far the building, a terrace or the pool extends beyond the slope – and whether the levels comply with the planning regulations, or by how much they deviate.

EM: How do you work with the often spectacular views?

LH: For us, what matters is how visual connections develop as you enter and move through the house, before revealing the full potential of the panorama. That’s why from the start we integrate the model into the topography at both medium and large scales – with reference points such as Palma Cathedral, Cap Andritxol or the Galatzó above Santa Ponsa, as well as the surrounding buildings or a nearby ridge. In this model we simulate the views from every point, inside and out. At the same time, we screen less attractive aspects and provide privacy, because those who see much naturally do not want to be seen too much themselves.

EM: What other aspects are particularly important to you?

AT: On steep plots we also attach great importance to the rear of the building. For natural daylight and cross-ventilation we use planted patios or voids with rooflights, which we like to fill with lush greenery.

LH: The landscape design must also allow inside and outside to flow together, even on steep terrain. We use solutions such as retaining walls in corten steel or large stone boulders, which enable us to integrate the project seamlessly into the slope.

EM: The design of different terrace levels with those striking Infinity Pools is particularly impressive in your projects.

AT: We often arrange terraces on several levels and zone the outdoor spaces with planting. In this way we create generous areas, avoid the need for balustrades between levels, and allow the design of the outdoor spaces to extend freely into the distance… after all, a villa on a slope should not feel like a Penthouse.

LH: There is hardly anything more beautiful than a long Infinity Pool where the waterline merges with the sea. On very steep sites, swimming pools are often the ideal way to control a higher edge of terrain. The overflow of the Infinity Pool can then be invisibly used from the house or terrace side as fall protection. Safety is especially important here: an overflow edge that is too high is not only unattractive from a distance, but also dangerous.

EM: Houses on slopes do not only enjoy wonderful views – they are also highly visible from afar.

AT: With hillside projects, the responsibility of the architect is particularly great. Integration into the landscape must always be the priority with these exposed sites. Unfortunately, there are far too many examples of pointless excavation and careless landscaping on what are otherwise magnificent slopes in the mountains or directly on the waterfront. We want our clients to be proud of their villa – not only when they live in it, but also when they see it from afar, for example from the sea.