For an average working-class family, the experience of urban life can only get as lavish as residing within a gated community, with measured spaces set aside for leisure. Even within the best of such communities, one is unable to come across unrestricted and ample spaces dedicated to a child's play. Every space within urban zones is demarcated and compartmentalised. Three metre wide pathways ‘only’ for vehicles, metal wire boundaries set in place to curb ‘unruly’ crossings within a residential area, staggered seating positioned across a multi-levelled expanse, for lodging ‘dynamic’ vantage points within a physically encumbered space. Our metropolises, under the garb of instating efficient functionality, pave the way for sections within an urban landscape that can readily be utilised only for commerce, for profit-making. These strict designations accorded to ‘cultured’ spaces can often make a place feel limited and tight, deepening the desire for the bucolic life, where the voids sustained in-between constructed premises can host a child’s play, an evening seance, a thoroughfare or the weekly market.

In the absence of vast empty stretches in our metropolises, the yearning for stretching horizons and verdant expanses exacerbates, amongst all of us. This ache to inhabit untempered landscapes is accompanied by the desire to construct homely abodes in such areas, a longing adeptly portrayed through a 2013 coming-of-age film The Kings of Summer. While it may be construed impractical to abandon one’s thriving urban life to recede into the wilderness, one should be permitted to imagine (and experience) periodic escapades to locales that can deliver this adventure.

Conflating this common desire with the technological provisions of modern times, architecture studio Arsenit designed Piil, an elevated retreat, or treehouse, nestled amid the Estonian forest. The Estonia-based architecture practice, founded by Arseni Timofejev, intends to place four such prefabricated structures within the forest. These positions were determined keeping in mind the responsibility to preserve the natural setting. The site was 3D-scanned by Hades Geodeesia. Upon this virtual site, the four Piil structures were positioned, to ensure that every tree branch could be accounted for, before setting up the cabins amid the verdant scape. This method also helped orient the structures such that their glazed surfaces offered spanning views of the dreamy sunsets upon the Jägala River. "While the 'leg' and the 'body' of the building can be dismantled and moved, if desired, moving the foundation and services is unlikely to be practical. That is why great care was taken when choosing a location for the building, using a detailed point-cloud model of the forest — to ensure minimal impact on nature, maximum effect in terms of views and integration with the existing trees," the architect shares.

The treehouse is named after the Estonian word ‘piiluma,’ which translates to peeking or looking. Timofejev compares the intonation of Piil with the English word ‘peel,’ exclaiming that it “fits with the aim of the project to peel away the mundane, the stress of every day—replacing it with a sense of calm and wonder that can be found amidst the treetops.” The first Piil treehouse, completed in 2023, is stationed near Estonia’s largest waterfall. The prefab home, nine metres tall, is a compact space, complete with a staircase and habitation space. “The client’s brief was for raised ‘glamping’ accommodation, which could be used as a retreat or a micro-hotel,” Arseni Timofejev, who hails from Tallinn, shares. “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-storey ‘leg’ elevates the accommodation 4.25 metres above ground—in future iterations, taller ‘legs’ could raise the accommodation units further into, or even above the tree branches,” he adds.

The cantilevered portion of the holiday home houses the main areas, while the ‘leg’ houses the staircase leading upwards, as well as the service stations and the sports equipment store. “Both ‘leg’ and the accommodation modules above act as large steel trusses—made in-house by the client, metal manufacturer Levstal Group,” Arsenit shares. The entrance of the residential architecture lies at its foot, positioned discreetly, with only a black handle jutting out to reveal its presence. A suspended terrace, imbued in the darker tint of black, serves as an open-air living room. By elevating the bedroom within the dwelling to a higher level, Timofejev not only minimises the presence of the structure at the ground level, hence reducing terrestrial obstructions, but also helps facilitate a unique vantage point and exceeding solitude in the raised room. From the cantilevered bedroom, the main wall of which is primarily fenestrated with glass, one can enjoy spanning views of the Estonian wilderness and experience the illusion of drifting amid the tall tree trunks.

The overall prefab design, standing at the height of 8.75 metres, is spread across an area of 19 square metres. Upon adding the areas of the mezzanine hammock hanging above the bedroom, the staircase living area or balcony, the storage area on the ground floor and the extruded terrace on the ground level, the area adds up to 51 square metres.

The foundation design of the structure, conceived on-site by AVC Projekt OÜ, comprises a frost-protected slab. "The foundation allows for service penetration (water, drainage and electricity), which are also frost-protected and insulated within the 'leg' of the building," Timofejev shares. All other components for this prefabricated architecture project were manufactured in a factory ex-situ. They were then delivered to the Estonian forest and assembled to build the final formations. Most of the individual components of the structure are connected to each other with the help of bolts. This helped preserve the sanctity of the space, by not turning it into a traditional construction site. The bolt-based connections also ensure the easy and quick dismantling of the modules, if the need arises. The off-site fabrication of the components (in the factory) also facilitated better workmanship. The result is a well-insulated cabin design with triple-glazed low-E glazing. Further, the ventilation, heating, cooling, and provision of warm water in this space are facilitated by an efficient air-source heat pump with MVHR (mechanical ventilation with heat recovery). During days that are cooler or hotter than usual, additional support from an integrated radiator or external condenser optimises the internal environment of the modular architecture unit. The rainscreen cladding of the structure also ensures better thermal insulation.

The metal skeleton of Piil is wrapped with untreated, thermally modified pine by Thermory. This material requires very little maintenance and weathers with time to carry a silver-grey hue. The tanned surface of the wood will, in the future, blend in seamlessly with the pine tree forest where Piil is positioned. The rectilinear cross-section of Piil, maintained across all axes, through the bends and the cinctures, adjoin visual depth to the structure, while also serving a monolithic appearance to the cabin.

When asked about the life span of the structure, Timofejev shares, "The building is designed to be used for at least 50 years — however it will hopefully last much longer! A lot depends on regular maintenance and construction quality by the contractor. It's important to note this is also a prototype, with a number of lessons learned that can be applied to future iterations of Piil to make it even better."

The interior design of Piil is ‘conceived as a large piece of joinery, all in white-washed oak.’ The different surfaces within the elevated bedroom are fixed such that they can be utilised for various purposes. A bench positioned below the glazed wall serves as a seating and relaxing space, as well as a table or workspace when one seats oneself down on the floor. Alternatively, the cavities positioned under the bench provide storage space, while the surface of the bench can be used as a display counter. In the same manner, shelves fixed between the wall and the bed, provide space for storage of personal items, while also serving as a staircase that leads up to the hanging net. The headboard of the bed, too, additionally accommodates a table on the other side, which is lit up to serve as a workspace or dining table. The interplay of horizontal and vertical surfaces within the structure pries very close to the hand-built treehouses found in backyards.

Piil, keeping in line with the current culture of remote work, offers ample space to relax and work within the cabin. It accommodates a king-size bed, ample storage spaces, two working tables, a kitchenette, and a washroom. Talking about the highlight of the cabin architecture, Timofejev shares, “The main highlight is the huge window and skylight paired with the generous hammock mezzanine — a place to feel suspended mid-forest, with nothing but the panoramic view ahead and the gentle sway of treetops above.”

All the habitable spaces, including the bedroom, the bathroom and the voids in between, are well-lit with natural light. One can simply look up and witness the crowns of surrounding pine trees dancing in the soft breeze. In order to avoid glare, each glazed surface fitted onto the wood architecture is further covered by opaque shading devices, permitting, hence, the influx of diffused light into the residential interiors. The usage of ample reflective surfaces, especially in the bathroom, helps disseminate the incoming light across the entire expanse of the snugly built treehouse. While natural light seeps into the cheerful space during the day, soft warm light filters out from the treehouse during nights.

Project Details

Name: Piil
Location: Estonian forest
Area: 51 square metres
Year of completion: 2023
Architect: Arsenit
Structural Engineers: SD Engineers; AVC Projekt OÜ
M&E Consultants: AS Infragate Eesti; ICEkonsult OÜ; Pat-Pat Projekt OÜ
Joinery: ITB Interior OÜ
Client / Contractor: Levstal Group