Journal

Vals, an isolated village situated at 1,200 m. above sea-level in a valley among the Grigioni mountains, boasts the presence of therapeutic spring water. The architect Peter Zumthor was asked to design a new spa complex in the proximity of an existing hotel, which was instantly acclaimed a masterpiece of contemporary architectural design. The architect himself describes the project as follows:
“The new building is a large stone construction with a grass roof, wedged into the mountain with which it forms a single body. It is a solitary structure rather different from the other, pre-existing buildings; the reason for this is that it was designed to underline another, more important feature: its intense relationship with the primitive energy and geological character of the surrounding mountains. In developing this idea, we liked to think that the building could give the impression of being older than the adjacent building, that is, a timeless presence in this landscape. Mountains, stone, water, building in stone, with stone, inside the mountain, building outside the mountain, being inside the mountain: the attempt to make architectural sense of this chain of words was what guided the project and, step by step, gave shape to it.”¹
Dominated by the horizontal dimension, the building consists of a large stone volume leant against the mountain slope, “hollowed out” inside in a sublime manner by means of a spatial continuum featuring differently shaped cavities in which the architect has only worked with light and shadow, with the mirror qualities of the pools or the densely opaque of the steamy air, with the different sounds that water makes when coming into contact with stone, and with the intimate feeling experienced by naked bodies during the ritual bathing.
As if carried into the hard interior of the mountain, the sequence of “geometric caves” is composed of large vertical blocks of stone around which the spring water runs or is collected; massive, compact pillars arranged in a calculated spatial order which, although perceptible, is never completely evident. While the building, which from the outside appears as a solid monolith, on the inside reveals its “hollowed out” nature, the pillars themselves are also hollow and accessible in a series of fascinating, somewhat isolated points.
Starting from the narrow shaded entrance corridors, the spatiality of the Vals Spa gradually grows in a crescendo of size, luminosity and perspective, producing a series of strong sensorial effects, as one wanders from pools of water at different temperatures to wall openings looking out over the Alpine landscape, through closed or communicating spaces with evocative names referring to the diverse “atmospheres” in the Spa (such as “the sounding stone”, “the fire bath”, “the massage block”, “the sweating stone” and so on).
The idea of the hollowed-out, subterranean character of the building led Zumthor to create a series of precise cuts in the ceiling, where the concrete slabs have been laid alongside each other without touching: “scalpel-like” incisions in the body of the building. These slits let in bright beams of natural light, which change according to the seasons and the weather; at certain times of the day, artificial light plays a supplementary, technical role. Fluxes of light that descend from above, graze the walls and further emphasise the material qualities of the stone, or filtered through coloured crystals, increase the magic aura of the Spa.
The internal and external surfaces of the parallelepiped’s walls are characterised by the uniform stratification of the local stone – a siliceous, schistose quartzite quarried one thousand metres higher up the valley, and cut into thin slabs or long ashlars of various sizes (31, 47 or 63 millimetres thick, and from 80 cm. to 2.5 m. long). These measurements are designed to complement one another and enable the stones to be arranged in such a way as to come up flush with the window and door frames and the stairwells, without having to modify the thickness of the masonry courses for the entire length of the walls.
The walls themselves are not made entirely from stone; the thin slabs, superimposed one upon the other, form a layer of stone cladding, from 12 to 15 cm. thick, laid on top of a base of reinforced concrete. What has been called the “Vals mixed wall” is a solid combination of a concrete nucleus and stone facing; the arrangement of the latter, laid with thin joints between one stone and the next – created using a special synthetic mortar – acts as a caisson for the reinforced concrete to which, in the end, it is permanently bonded.
The building was constructed by building sections (consisting of several masonry courses) of about 80 cm. in height each time, so as to avoid the stones coming apart when the concrete was poured into the interstice behind the masonry facing. The individual stones, separated by almost imperceptible joints, appear as very thin, carefully staggered listels, giving the facing an unusual contemporary design, almost as if it were a grey-green fabric of a vibrant lightness.
Beneath its apparent simplicity, the entire building conceals a carefully conceived wall design by means of which Zumthor wished to reinforce the monolithic homogeneity of the structure dominated by the principle of stratification.
The stone descends from the walls in a basically continuous manner, onto the pavement, where the stone slabs get wider and create an opus quadratum pavement design, often varied and part of an overall “spiral winding” composition, following the spatial cells of the spa pools, or of a rectilinear axial nature, indicating the main ways out of the building to the open-air pool.
Here, as with the interior, the horizontal rhythm of the wall’s stratification proceeds in a continuous fashion along the steps’ risers which descend below the water level to the bottom of the pool. Architectural details such as the “overflow” continue – along a horizontal plane – the fascinating story of the stone from Vals; their “heterogeneous” impermeable joints and the stainless-steel channels, fit in well with the vibrant stone material, so that the observer is not distracted by them, and perceives just the stone itself.
This idea of continuity and homogeneity, which is peculiar to Zumthor’s architectural style, may be considered perhaps the most meaningful, “generative” feature (together with the contribution made by light and space) of the aura of Vals Spa.
The Swiss architect who designed the Vals complex has the following to say about architecture in general: “Architecture is called upon to create a whole from innumerable individual components having different functions, and of diverse shapes, materials and sizes. For corners and joints – those points where surfaces intersect and diverse materials meet – we need to design meaningful constructions and shapes. These special shapes are used to establish the delicate intermediate measurements within the main proportions of a building. The details define the formal rhythm, the proportional refinement of the scale of a building.
Details have the task of expressing that which the basic design requires in that particular point of the object: union or disjunction, tension or lightness, friction, solidity, fragility (…). Details, when they are successful, are no mere decoration. They do not distract or entertain, but induce the observer to understand the whole, to whose essence they necessarily belong”.²

Alfonso Acocella

¹ Peter Zumthor, “Le terme di Vals. Pietra e acqua”, Casabella no. 648, 1997, p.56.
² Peter Zumthor, Pensare architettura, Baden, Lars Müller Publishers, 1999, p.16.