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5 trees
10 half-trees
140 thousand visitors
Ratatosk at the V&A
Part of the "Architects Build Small Spaces" exhibition at the V&A Museum in London
London, UK
V&A Museum


Ratatosk is the squirrel who there shall run
On the ash-tree Yggdrasil;
From above the words of the eagle he bears,
And tells them to Nithhogg beneath.

From Grimnismol, translation from Old Norse by Henry A. Bellows

We began our work on this project with recalling how we used to play in our favorite trees in the forest. There was no differentiation between spaces created through play and play in itself. This raised the question of how we can recapture this embedded interwoven reality of play, reflection and experimentation.

“Ratatosk” was designed in an analogical mode, through a sequence of playful encounters and empirical steps: selecting trees, 3D scanning, 3D modelling, exploring, CNC milling, assembling and synthesizing them into a new whole.

Our site, the courtyard of V&A Museum in London, with its proximity to the elegant red brick museum building, prompted our decision against the design of a small traditional building. Instead, referring the to the long tradition of British park architecture, we created a “tree folly”.


After extended research for the selection of a suitable tree species, we chose locally sourced pollarded/coppiced ash trees. The selection fulfilled the needs of our initial design intent, with their characteristic short trunks and spindly branches. The trees were cut at their bases and split, then scanned and 3d modelled, so as to be ready for our digital interventions.

Scaled plastic prototypes enabled us to experiment, both virtually and physically, with positioning of the 10 half-trees in relation to each other. The trees were ultimately connected in a ring, their trunks linked at their branches, maximising stability and stiffness, eliminating the need for any additional structural support. The ring achieved the spatial quality we envisioned: an intimate but, at the same time, airy and open assembly.

After the trees were positioned, we designed a CNC milling pattern which unified the interior surfaces of all ten half-trees, while. The milling reflected the trees’ intrinsic qualities such as fiber direction, formation of branches as well as their performative potential for activities such as climbing, sitting, imagining etc. The smooth refinement of the interior surface of the trees contrasts starkly with the rough bark exterior.

All parts of the trees, trunk, bark, wood chippings, roots and branches were refined and assembled together into a new whole. The roots were milled and grafted with additional support and serve as fundaments. Trunks and roots are connected with slotted in timber-taps. The roof is woven of sliced branches, which are mounted to the branch-stumps. Bark and wood chippings filled into netting created pillows are moulded and utilized as a soft play and protecting landscape. The result is a prefabricated kit, which was developed on a number of integration levels simultaneously, and challenged the traditional sequence of the design process.

Team: Reinhard Kropf, Dag Strass, Caleb Reed, Elliet Spring
Timber engineering: Creation Holz; Hermann Blümer

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