arsenit’s prefabricated treehouse suspends over a terrace in the estonian wilderness

arsenit tucks piil treehouse in the estonian forest

Piil, named for the Estonian word ‘piiluma’ for ‘peeking/looking’, is a nine-meter-tall and pre-fabricated treehouse signed by studio Arsenit. With a compact plan, the 19 sqm retreat is elevated to minimize ground-level presence while providing scenic views of the vast Estonian wilderness. It stands on one ‘leg’, suspended over a terrace, creating an open-air ‘living room’ sheltered from rain and snow. A discreet door provides access inside, with the cladding layer peeled back to reveal the metal structure supporting the impressive cantilever. Both ‘leg’ and accommodation modules above act as large steel trusses — made in-house by the client, metal manufacturer Levstal Group. Wrapped in hit-and-miss pine cladding, the ‘leg’ contains a staircase, services, and a sports equipment store. The raised bedroom provides greater seclusion, a unique vantage point, and an opportunity to rest among tree branches.

an elevated 19sqm retreat for remote work and rest

The interior of the Piil treehouse by Arsenit (see more here) is conceived as a large piece of joinery, all in white-washed oak. The interplay of levels allows horizontal surfaces to be used informally as tables, seats, or display spaces, while the vertical timber paneling adds a tree-house-like quality. The living spaces also offer the facilities for remote work and comfortable rest: a king-size bed, two working tables, a kitchenette, ample concealed storage, and a generous bathroom with a top-lit shower. A highlight of the retreat is the huge window-skylight paired with a large hammock mezzanine where its residents can feel suspended mid-forest.

well insulated, timber-paneled, and prefabricated

Externally, the Piil treehouse is finished in untreated, thermally modified pine by Thermory — a material that requires little maintenance and will weather gracefully to a silver-grey, helping the building blend in with the pine tree forest in which Piil has been carefully placed. The use of this rain-screen cladding with a square cross-section adds visual depth; filters light and air into the building while giving it a monolithic appearance; provides shade to the openable window; encloses a ground-level storage space; screens services and MVHR grilles. Finally, the directionality of the timber cladding accentuates Piil’s unique form.

All elements of the Piil treehouse are designed to be finished in a factory off-site and then delivered to remote and scenic locations, where they are assembled into a whole. Off-site fabrication means a higher level of workmanship, resulting in a well-insulated accommodation unit with triple-glazed low-E glazing. 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.

planning four piil treehouses on site

The team at Arsenit completed the first prototype of Piil in early 2023. In total, four Piils are planned for the site, carefully positioned using a point cloud model of the forest to frame sunset views of the Jägala River. Arseni Timofejev, founder of Arsenit, reflects on the project: ‘The client’s brief was for raised ‘glamping’ accommodation, which could be used as a retreat or a micro-hotel. Inspired by the observation towers placed in scenic locations throughout Estonia, Piil imagines what it would be like to stay in one overnight. In the first prototype version of Piil, a single-story’ leg’ elevates the accommodation 4.25m above ground — in future iterations, taller ‘legs’ could raise the accommodation units further into, or even above the tree branches!‘

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project info:

name: Piil

location: Estonia 

architecture: Arsenit | @arsenit 
client / contractor: Levstal Group
structural engineering: SD Engineers, AVC Projekt OÜ
M&E consultants: AS Infragate Eesti, ICEkonsult OÜ, Pat-Pat Projekt OÜ
joinery: ITB Interior OÜ

photographer: Yifan Liu