vertical timber cladding coats compact karaka tower treehouse in new zealand

Arête Architects construct Karaka Tower on Eastbourne hillside

Karaka Tower, designed by Arête Architects, stands as a pragmatic solution to a complex steep site in New Zealand and an open-ended client brief. The owners’ desire for additional space amidst a challenging terrain and an existing home led to the inception of this innovative annex, providing a supplementary bedroom and art studio. Nestled within the native bush of Eastbourne, Wellington, this modest 9 sqm tower exemplifies architectural ingenuity and functionality.

The tower’s design focused on maximizing space with minimal footprint, achieved through stacked modular volumes. Prefabricated in a factory, these modules were airlifted onto a preformed platform, showcasing architectural, construction, and coordination prowess. While not directly contributing to the community, the Karaka Tower sets a precedent for modular construction, unlocking potential across undeveloped sites.

Situated on a heavily vegetated steep hillside, the tower harmonizes with its surroundings while offering views of Te Whanganui-a-Tara. The construction method, driven by site access constraints, facilitated helicopter transport in three parts, each weighing a maximum of 1100 kg. Material selection prioritized environmental integration and construction flexibility. The eucalypt rainscreen blends seamlessly with the landscape, requiring minimal maintenance over time.

all images by Thomas Seear-Budd

timber framing on the interior achieves a treehouse-like feel

To accommodate the prefabrication and on-site stacking of the building, a new waterproofing system was crucial. The design incorporated exposed macrocarpa timber framing on the interior for a treehouse-like feel. A rigid air barrier and thermal polystyrene were layered over the framing, creating an airtight and fully thermally broken skin. To prevent direct fixing penetration from the exterior to the interior, a double TPO membrane and batten system was implemented. The modules featured 300 mm membrane laps, allowing for onsite welding to ensure swift weathertightness. This detailed solution was a collaborative effort between the design team and Viking Roofspec, tailored specifically for the project.

Efficiency was paramount throughout the project, with groundworks and building work proceeding concurrently. The lightweight construction materials and exposed design enable easy maintenance while minimizing environmental impact. Prefabrication in a controlled factory environment maximized efficiency and minimized waste, contributing to the project’s sustainability.

Thermal performance optimization and strategic detailing further enhance the building’s functionality and longevity. The decision to airlift the tower minimized construction disruption and potential environmental impacts, showcasing a thoughtful approach to design and execution.

the strong linear nature of the tower is contrasted with the oblique form of the vestibule

the design maximizes space with minimal footprint, utilizing stacked modular volumes for efficiency

the need for additional space led to the creation of this annex that serves as both a bedroom and art studio

polycarbonate was used to give a sense of privacy while still outlining the craftsmanship of the structure

the design incorporated a rigid air barrier and thermal polystyrene for an airtight and fully thermally broken skin

set in Eastbourne’s native bush, the tower’s roof garden terrace became a focal point of the project

situated on a steep hillside, the tower offers views of Te Whanganui-a-Tara harmonizing with the environment

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screen printing studio

tools of the trade

framed tree views

pine and macrocarpa interior detailing

project info:

name: Karaka Tower
architect: Arête Architects | @aretearchitectsnz

construction: Makers Fabrication

location: Eastbourne, Wellington, New Zealand

photography: Thomas Seear-Budd | @thomasseearbudd

designboom has received this project from our DIY submissions feature, where we welcome our readers to submit their own work for publication. see more project submissions from our readers here.

edited by: christina vergopoulou | designboom