Project Site and Natural Context

Casetta Tessino is located in a dense oak forest in the Swiss Onsernone Valley, within a natural environment subject to strict zoning regulations. These restrictions were not a minor detail but formed the governing framework for any potential architectural intervention on the site.

Constraints as a Design Generator

When the site owner, a climate activist and artist, wanted to add new living space, he faced a complete ban on conventional additions or any ground-based foundations. Consequently, the solution was not horizontal but vertical, exploiting the only available element: the trees themselves.

Architectural Concept and Design Response

Architect Olin Betzold approached these constraints as a design opportunity rather than an obstacle. The building takes the form of a balanced triangular structure resting on three trees, elevated above the forest floor without disturbing it. This solution reflects an approach that respects the environmental context while redefining the concept of architectural foundation.

Materials, Light, and Function

The exterior envelope is composed of a mix of wood and semi-transparent polycarbonate panels, allowing filtered natural light to enter and softening the visual harshness within the small interior. Functionally, the building, located approximately 150 meters from the main house, serves as a writing studio, guest room, and quiet retreat simultaneously.

Hidden within the greenery, Casetta Tessino redefines the relationship between built space and the natural landscape. (Image © Giacomo Albo)

Operable elements like pivoting windows allow for natural ventilation and a direct tactile connection with the surrounding air. (Image © Giacomo Albo)

Intellectual Reference of the Design

The project consciously draws on the ideas in Henry David Thoreau’s Walden, evoking the philosophy of simple living and direct immersion in nature. This reference was not merely symbolic but formed the actual foundation for every design decision, from material selection to the organization of interior spaces. As a result, the building favors contemplation and creative work, moving away from the conventional notions of comfort associated with everyday dwellings.

Self-Building as a Design Necessity

Adopting a self-build approach played a crucial role in shaping the project. The remote location excluded the possibility of using heavy machinery, which required all elements to be lightweight, portable, and suitable for manual assembly. This constraint led to simplified construction details, enabling execution without advanced professional skills.

The Owner’s Role in Execution

The owner personally carried out the entire construction, translating architectural drawings into a realized structure through careful, incremental manual work. This choice was not solely driven by economic considerations or personal preferences but was a direct response to the realities of the isolated site and the nature of the treehouse, making the construction itself an integral part of the project’s intellectual and architectural experience.

The use of translucent panels transforms the cabin into a glowing lantern at night and a blurred canvas of nature by day. (Image © Giacomo Albo)

Interior spaces are designed as observation decks, framing the forest as a living mural. (Image © Giacomo Albo)

Interior Organization and Triangular Geometry

Inside, the triangular footprint plays a key role in maximizing the limited space. Since the owner’s main house combines living, kitchen, and bedroom areas within a single room, there was a clear need for a separate, quieter space. Here, the treehouse functions as a practical extension, providing genuine isolation without expanding the footprint.

The triangular base rests on the three supporting trees, then gradually rotates into an inverted equilateral triangle, with its corners threading between the trunks. This geometry creates a clear separation of sleeping, sitting, and writing zones within a highly minimal architectural envelope.

Shared Use and the Living Experience

The cabin is not limited to the owner’s use; it remains accessible to other creatives, making the experience of staying there continuously renewed. Each user experiences how architectural design can directly influence the rhythm of daily life and the nature of creative practice.

Plywood surfaces and essential furniture emphasize a life stripped back to the basics in the heart of nature. (Image © Giacomo Albo)

Precision in timber joinery ensures the structure's stability while celebrating traditional woodworking in a modern context. (Image © Giacomo Albo)

✦ ArchUp Editorial Insight

From a positive standpoint, Casetta Tessino provides a clear example of how strict environmental constraints can be transformed into a design opportunity. It reflects a profound respect for the natural context and embodies the spirit of innovation in using trees as structural supports, while achieving harmonious natural lighting and functional flexibility within a small footprint. This approach offers a model that architects can draw upon when considering projects with minimal environmental impact or in remote locations.

However, several reservations emerge at the level of practical architecture and future expansion. The narrow triangular design and limited size may restrict long-term functional flexibility, while the complete reliance on manual construction at a remote site imposes limitations on the building’s structural and developmental capacity. Additionally, the lightweight, transparent polycarbonate envelope may pose challenges regarding thermal control and acoustic insulation over time, particularly in a variable mountainous environment. From the perspective of expansion or intensive communal use, the project may require adjustments to enhance daily comfort without compromising its original design philosophy.

In summary, Casetta Tessino remains an inspiring experiment in engaging with nature and design constraints, offering valuable lessons in innovation within strict limits. At the same time, it reminds architects of the importance of balancing aesthetic vision with functional requirements, as well as considering operational sustainability and future flexibility.