Europe’s first mass timber hospital building

Arlesheim Clinic builds according to anthroposophical principles

Article by Raphael Zeman (translated by Eva Guzely) | 02.12.2025 - 10:14

In 1921, Dr. Ita Wegman founded the clinic in Arlesheim, not far from Basel, with the support of Rudolf Steiner. The site has grown steadily for over 100 years. Today, however, the buildings no longer meet modern requirements for hospital construction. Therefore, the client decided to commission a new building, using adhesive-free dowel wood, that will house the remedy laboratory and the hospital.

This is what the Arlesheim Clinic will look like after its opening in early 2027 © ARGE 9grad architektur + BSS Architekten

The Arlesheim Clinic is an acute care hospital with a large outpatient department and offers inpatient treatments in the areas of internal medicine, oncology, and psychiatry. The holistic concept of integrative medicine encompasses conventional and anthroposophical therapies, holistic care treatments, eurythmy, and art therapies. Furthermore, for over 100 years, the clinic has manufactured its own remedies almost exclusively by hand. The range now includes around 600 remedies and numerous care products, most of which are produced using plants from the clinic’s own garden.

The aging building is now being modernized. The first step was the construction of a new remedy laboratory, which was completed in 2023. The new hospital building is currently under construction and will open in early 2027.

International collaboration

The two new buildings are the result of an international planning collaboration. While 9grad architektur from the Netherlands was tasked with the anthroposophical and organic design, Swiss firm BSS Architekten is primarily responsible for the successful construction. Hospital and medical technology planning firm MedPlan Engineering worked with the users to develop the optimal processes and select the ideal medical equipment for the clinic. Thanks to the diverse, specific expertise, the project team succeeded in developing sophisticated problem analyses, creative solutions, and ultimately an intelligent and contemporary design.

Anthroposophical and healing architecture

IHF Special 2025_Klinik Arlesheim_5.jpg — © ARGE 9grad architektur + BSS Architekten

The planning team followed the principles of anthroposophical architecture, which focuses on human health and vitality and aims to promote awareness of the health phenomena at work inside a person’s own body. The aesthetic and health-promoting design approach places great emphasis on balanced proportions and polarities, the coordination of inside and outside, and of the detail and the whole.

The principle of healing architecture was also taken into account in the design process. According to this principle, buildings have a positive influence on human health. During the design process, the team jointly raised awareness of the need to construct a building that supports vitality, helps reduce stress, and radiates calm. As a result, the planners paid particular attention to aspects such as acoustics, looks, materials, smells, daylight, colors, and orientation. For example, the pathways are laid out in such a way that windows are located in the direction of the main axes, thereby creating a connection to the outside and aiding in orientation.

The color scheme, which runs from bottom to top, tells its own story. On the ground floor, shades of green reference the surrounding park. As you move upwards, the colors become increasingly warmer, until shades of orange on the top floor convey warmth and a sense of a protective environment.

Built in mass timber at the client’s request

IHF Special 2025_Klinik Arlesheim_6.jpg — Approximately 246 m³ of adhesive-free dowel wood creates a feel-good atmosphere designed to help patients recover © ARGE 9grad architektur + BSS Architekten

Both buildings – except for the basement, base floor, and access cores – are being constructed using the Holz100 mass timber construction system. The individual elements are connected with wooden dowels; adhesives, metal, chemicals, and wood preservatives are not used. The client specifically requested this construction method due to its health-promoting, ecological, and aesthetic properties. Holz100 uses only moon wood, which is harvested during the waning or new moon in winter, as fluid transport in the tree is lower during that time of year. Therefore, the wood is said to be denser, more durable, and more resistant to pests.

A total of around 246 m³ of adhesive-free spruce and fir wood from the sawmills of Holz100 Schweiz (Thoma Holz) were used. 25-cm-thick dowel timber was used in the exterior walls, while a thickness of 14 cm was used in the interior walls, and of 21.5 cm in the wood-concrete composite ceilings.

The posts are made of natural wood, and the flexible wall structure consists of doweled individual elements, thus effectively counteracting the horizontal forces that occur during earthquakes. The façade was insulated with soft wood fiber boards, and wooden windows were installed. The façade consists of 24-mm-thick, untreated larch cladding, and the boards can be removed in the base area.

Five aspects of sustainability

IHF Special 2025_Klinik Arlesheim_4.jpg — © ARGE 9grad architektur + BSS Architekten

Generally, the client had demanding requirements for sustainability in the project. For example, in an interactive process, five central sustainability themes with a focus on building biology were developed. First, they opted for natural, unadulterated materials and renewable raw materials with a positive environmental impact. Those should be processed as authentically and perceptibly as possible – in other words, in visible quality. Second, the sensory impact of the building was considered crucial. The materials should therefore have a pleasant smell and be free of toxic fumes, toxins, and allergens. The third aspect chosen was natural moisture regulation through vapor-permeable materials such as wood and clay.

Furthermore, the consistent use of renewable energies was a major priority for those involved. For this purpose, the wood-concrete composite ceilings were equipped with a component activation system. This is a low-temperature system in which pipes containing heated or cooled water are laid inside the floors. This energy-saving method creates a pleasant and comfortable indoor climate and, thanks to hot water storage, the heating does not need to be turned on when heat demand is low. Finally, the team wanted to use locally and regionally sourced raw materials – which is one of the reasons why they chose moon wood from the Black Forest.

A clinic that sets an example

IHF Special 2025_Klinik Arlesheim_1.jpg — As part of the new construction, the surrounding park, to which the buildings’ design refers, was also redesigned © ARGE 9grad architektur + BSS Architekten

By minimizing energy consumption and using solar energy, the new buildings meet the Minergie P standard and, according to the architects, store over 2,000 tons of CO2. This flagship project thus takes the environment into account. And the people? The bright, natural, chemical-free components and wooden surfaces have a positive effect on the mood and well-being of people; warm colors and plenty of daylight create a pleasant atmosphere. Well-thought-out visual and spatial concepts create a feeling of security.

All of these factors – like the natural and largely handmade remedies used at the Arlesheim Clinic – contribute to the recovery of patients. Hopefully, this project will inspire others to built in a similar way.