Arsenit designed this innovative little retrat nestled deep within the enchanting pine tree forests of Estonia. Named ‘Piil,’ which is derived from the Estonian word ‘piiluma,’ meaning ‘peeking’ or ‘looking,’ this 9-meter tall pre-fabricated treehouse redefines the concept of eco-friendly retreats.
Designed to provide an immersive connection with the natural surroundings while minimizing its ground-level presence, Piil offers visitors generous views of the vast Estonian wilderness. The 19-square-meter structure stands gracefully on a single ‘leg,’ artfully suspended over a terrace, creating an open-air ‘living room’ that shields occupants from rain and snow. A discreet door provides access to the interior, revealing the metal structure supporting the impressive cantilever. The ‘leg’ and the accommodation modules above act as large steel trusses, all expertly crafted by the Client, metal manufacturer Levstal Group.
Wrapped in hit-and-miss pine cladding, the ‘leg’ serves as a multifunctional space housing a staircase, essential services, and even a sports equipment store. The elevated bedroom offers seclusion, a unique vantage point, and the opportunity to rest among the tree branches.
Inside, Piil boasts an interior conceived as a large piece of joinery, adorned entirely in white-washed oak. The interplay of levels allows horizontal surfaces to be used informally as tables, seats, or display spaces, while vertical timber paneling adds a tree-house-like charm. Piil is equipped to facilitate remote work and comfortable rest, featuring a king-size bed, two working tables, a kitchenette, ample concealed storage, and a generous bathroom with a top-lit shower. The pièce de résistance is the enormous window/skylight paired with a generous hammock mezzanine, offering an unparalleled experience of being suspended mid-forest, with nothing but the panoramic view and the gentle sway of treetops.
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Externally, Piil is finished in untreated, thermally modified pine by Thermory—a low-maintenance material that gracefully weathers to a silver-grey, blending seamlessly with the surrounding pine tree forest. The rain-screen cladding with a square cross-section adds visual depth, filters light and air into the building, and provides shade to the openable window. It also encloses a ground-level storage space and screens services and MVHR grilles. The directionality of the timber cladding accentuates Piil’s unique form.
One of Piil’s standout features is its off-site fabrication, where all elements are meticulously designed and finished in a factory before being transported to remote and scenic locations for assembly. This approach ensures a higher level of workmanship, resulting in a well-insulated accommodation unit with triple-glazed low-E glazing. For climate control, an efficient air-source heat pump with MVHR provides ventilation, heating, cooling, and hot water throughout most of the year, with additional support from an integrated radiator or external condenser on particularly cold or hot days.
The first prototype version of Piil was completed in early 2023, and there are plans for a total of four Piils on the site. These structures have been carefully positioned using a point cloud model of the forest to frame stunning sunset views of the Ja?gala River.
Project information
Architects: Arsenit – www.arsenit.com
Area: 19 m²
Year: 2023
Photographs: Yifan Liu
Architect and Lead Designer: Arsenit
Structural Engineers: SD Engineers, AVC Projekt OÜ
M&E Consultants: AS Infragate Eesti, ICEkonsult OÜ, Pat-Pat Projekt OÜ
Client And Contractor: Levstal Group
Joinery: ITB Interior OÜ
City: Jägala-Joa
Country: Estonia
