Natural stone as a building material has held prominence for aeons, competently finding a secure place in articulating modern buildings as well. Stone’s uniqueness and discipline surface into crafted forms of sculptural poise, a clear sense of endurance and vitality, as well as gentle self-assurance, placing it as a consequential partaker in the evolving landscape of architecture.

At the heart of Haus Balma in Vals, Switzerland, designed by Kengo Kuma & Associates, lies an innate reverence and subsequent incorporation of a certain Swiss stone, known, appreciated, and desired by many architects for its impressively high performance, distinct, classy demeanour, as well as its allied applicability as a building material: the Vals quartzite features a resplendent silver metallic glitter and a gorgeous colour range that shifts and dapples from green to blue when it encounters water or natural light. In Haus Balma, Vals stone ends up as one of the protagonists, engaging at intervals with glass and wood, aspiring “to showcase the potential and the exceptional quality of Vals stone with unique manufacturing techniques, innovative details, and applications,” as Kengo Kuma & Associates (KKAA) shares.

With traditional Alpine houses filling up its steep, narrow valley snaking among mountains, the Vals village in Switzerland boasts a scenic setting. In its bare rock state, the terrain's Vals quartzite is incorporated as rough splits of solid stone slates and applied onto the roofs of traditional houses, establishing the village’s scenery. One succinct example of a recognised architect embracing and utilising Vals quartzite as a modern building material is Peter Zumthor, whose sensory and alluring project, Therme Vals (1996), employed 60,000 slabs of it most poetically and exquisitely, revealing theatrical, confident architectural delights with stone.

From a distance, Vals, with its houses crowned with stone-tiled shingle roofs gives off a remarkable appearance of stones floating above the valley—this visual was taken as a primary reference for Haus Balma, where KKAA attempted to capture and emulate this within the details of the Swiss architecture. “The architecture with, and made of Vals stone, is designed to echo the surrounding nature and the architectural language of the village,” they recall.

A calm, composed alchemy of textures gives rise to a mature and hybrid expression defining the stone architecture, which is also referred to as the Truffer Stone A.G. Headquarters, owing to its clients—the Truffer company process extracted natural stone in Vals, processing them in a local factory for its subsequent application across various architectural elements including roofs, floors, facades, and more. Interestingly, the Vals Stone manufacturer Truffer Stone A.G commissioned Kengo Kuma & Associates a brief for its new headquarters and showroom in the country, minus ‘any specific purpose’ and sans ‘any spatial program to implement.’

On how its programming was deliberated on and finalised in the face of such a brief, Yuki Ikeguchi, partner in charge/ executive vice president, Kengo Kuma & Associates, tells STIR, “We developed the spatial programme through a series of dialogues during the design process. The process was extensive, but we got to take part in many family meetings and gatherings to learn about their ways of life and business. I believe the close dialogue with the family made our design special, one that fits their life and work style. We made many trips to Vals during the design and construction, and that makes me feel nostalgic when I think about it now.”

Stone-cast voids of pauses, beauty, and shelter

Haus Balma, in regional terms, refers to “a void, a space between a piece of rock, and the sloping land where animals and humans can be sheltered for comfort and safety in a mountain,” explains the project's design team led by Japanese architect Kengo Kuma and Ikeguchi. “It is our hope that the project would grow to be organic to its land and become a place for comfort and nesting for the family and the community,” they continue.

According to them, Haus Balma’s architectural volume was generated to fit the site’s constraints, as was the case with the pitched roof shape adhering to local building guidelines. Thereafter, this recognisable architectural feature of surrounding traditional Alpine houses was contemplated, with the eave proliferating as the project’s design motif. The form, furthermore, is also reminiscent of Japanese pagodas, as much as the tiled roofs defining Vals' traditional architecture.

“We derived an architectural form to echo the surroundings and to create the spatial experience as interpretation, and extension of natural settings in Vals,” Ikeguchi shares with STIR. “We drew inspiration from the vernacular architecture with pitched stone roofs. The roofscape in the backdrop of the narrow valley creates specific scenery. Our building’s form is derived from the reinterpretation of this pitched roof language. Eaves following the shape of the roofs are expressed at each floor level to be perceived,” she adds.

A floating stone curtain

One of the project’s most intentionally crafted features is its seemingly levitant, almost mystical facade design, articulated through slabs of slender stone and wood, and metal threads, which together, seem afloat in reverie. According to KKAA, this exterior envelope design was developed from the traditional eaves with rough split stone slabs, drawing them down in a manner resembling a screen, with a dominant, delightful contrast of stone appearing almost weightless. “In traditional Alpine houses, windows are small, [and] thus, spaces would feel cosy and more protected. In this project, our design intention [was] to create openness with more sense of transparency, to take in incredible views of the mountain as a part of [the] interior backdrop,” they elaborate.

Stone slabs and larch plants supported by stainless tension cables give life to this permeable curtain. These are fixed on recessed stainless-steel clamps that are milled at precise angles to match the shutter-like structure’s inclination. “By minimising the dimensions and visibility of the metal fittings and the supporting structure, the screen gives an effect of slates of stone staying gently and subtly afloat in front of the window. The intricate details and precision were possible through a series of trying, testing, and challenging manufacturing methods, [as well as] techniques and learning from the masters of stone, the Truffer family,” elaborates KKAA, which has offices in Japan, France, China, and more.

The clear incorporation of Vals quartzite stone in the contextual design, which is ‘the’ protagonist spelling the exterior as well as the interior, speaks to its site, its vernacular built language, as well as the client’s space in it. “We wanted to create an architecture that exhibited the full potential of Vals quartzite, from the application of details, and finishes, to its tectonics. The exterior screen was one of the more elaborate designs in the structure. We designed it with a suspension structure where the stone is thinly sliced and attached to tensioned stainless steel cables. Metal fixing pieces were engineered and designed to fit within the thickness of the stone plate so that only the cables and stones were visible. A sense of lightness was achieved in contrast to the image of stone being heavy. The whole façade became quite transparent, with a delicate expression of stone being achieved. One panel of suspended stone, is in fact, composed of two thinly cut slabs. They are laminated together so to gain stiffness and elasticity to absorb movement. This detail was considered for safety measures, in case it cracks, and continued instead, to hold it together,” Ikeguchi explains.

A heart of stone

Hauz Balma’s interior design too, reflects, integrates, and worships Vals quartzite, as deliberately and pleasingly as its skin does—here, the generous spatial dimensions, the play of open and private areas, the overall arrangement, as well as the lighting, are seemingly impressed and composed to recreate the sensation, visual, and experience of being inside a quarry, or a crack of monumental rock. Inside, the devised height of the architectural volume is successful in linking all programs through stone.

As Ikeguchi shares with STIR, intricate triangular spaces express the insides of the Truffer Stone A.G. Headquarters, which are structured and organised around a central, linear void, where a staircase design runs diagonally and vertically through its entire length. Here, the staircase was provided with an exaggerated, narrow, and tall proportion, further defined by two walls with massive, raw split stoneface with boreholes, giving it a gorge-like feeling. “It is a symbolic space, reminiscent of the quarry that is essential and fundamental for the Truffer family,” Ikeguchi reiterates.

The generous spatial planning, therefore, was developed around this central staircase, comprising a level underground and four storeys above ground. The contemporary architecture’s basement houses the ‘stone world’ (as coined by the design team), a spacious, underground level infused with a ‘subterranean atmosphere’ housing a showroom, meeting, and gathering space, (for multiple purposes as such as lectures, presentations, meetings, and exhibitions) with its own showcase bathroom, as well as a sunken garden gently awash by a skylight placed over them. The skylight here is designed with a minimum supporting structure to accentuate the stone texture and intended sensation of being in the stone crack, categorically directing only determined bands of natural light to enter.

“The space is symbolic of the quarry being the core and the foundation of the family work, their invention and creation,” Ikeguchi relays. In tandem, the ground floor is a welcoming space, open and visible from the street, designed to receive visitors and clients, as per the project lead. The first and ground floor host office functions, “where workers can enjoy views all around at the elevated level,” she adds. The second and third levels are employed as private residences, “where calmer and more intimate scales under the sloped roof can be experienced,” she says.

Here, the screen façade is composed of stone and timber plates in a mixed pattern. “The portion of the stone plates in the screen is more in the lower levels, and it would gradually decrease at the higher level with more timber plates. At the residential upper levels, one would feel the texture of wood more, seeing it from the interior. The timber that we used here is larch, as it is commonly used for the surrounding buildings. Over time they will turn grey, to merge in tone with Vals quartz stone,” Ikeguchi conveys to STIR.

A rare intervention, the contextual architecture discloses care and attention to detail, integrating stone as an almost living entity: flying, swaying, dormant, structural, introverted and extroverted. Attesting to its properties and colour palette, the building blends pleasantly into the local environment of the alpine town, without disturbing it. Making friends with wood, metal, and glass, the primary stone materiality of Haus Balma, among its many commendable features, elevates the project into a composed marvel that respects its site, as much as its vernacular built history, with an attractive, collected, solid material that promises to endure as it matures.

Project Details

Name: House Balma
Location: Vals, Switzerland
Area: 1,262 sqm (site area); 1,365 sqm (total floor area)
Client: Truffer AG
Architect: Kengo Kuma & Associates: Kengo Kuma, Yuki Ikeguchi (Partner in charge); Yasemin Sahiner (project manager); Jagoda Krawczyk (project architect)
Local Architect: Spreiter+Partner AG, Robert Anacker
Façade/ Structure Engineer: Mario Russi, REBA
Lighting Design/ Fixture: Viabizzuno