Prototyping Vienna

Loam plasters and acoustic panels, made from the clay a city digs up and throws away.

Year

Summer 2025

Studio

Act of Building, Act I · TU Wien

With

BC architects & studies & materials

Team

Eva Buder, Elisa Geiser, Florian Ocenasek, Marlies Weidinger

Result

1:1 prototype, exhibited

Supervision

Thomas Amann, Prof. Tina Gregoric

Made with

Excavated Wiener Tegel, Japanese knotweed, reed, crushed brick, hand-applied plaster

Loam plasters and acoustic panels, made from the clay a city digs up and throws away.

The prototype as exhibited

Angled view of the prototype's roof and wall assembly cut open, tile, wood-wool and timber layers exposed

Roof-to-wall section, tile and wood-wool exposed

Close-up of the eave junction, reed thatch, wood-wool insulation, plaster and timber beam meeting

Detail

Vienna excavates 4000 tonnes of usable Tegel every day during metro construction, and discards nearly all of it. Plenty of other ecological materials get treated the same way. We worked inside that overlooked flow, taking waste as a possibility rather than a problem.

The question was how those materials could re-enter the city's building culture through simple, low-tech means. We chose two applications, interior loam plasters and acoustic panels, built from excavated Wiener Tegel, invasive knotweed and reed, and crushed brick.

Four raw materials in close-up, wet grey Tegel loam, chopped knotweed and reed, dry sand-loam, and crushed brick powder — Materials

A mound of crushed brick with a bucket and a rake, sourced from around the city — Sourcing crushed brick

Over 20 plaster recipes went onto test boards. Higher clay content spread better but cracked as it dried, which chopped reed and knotweed fixed. Crushed brick added abrasion resistance and a warmer colour. How the loam was prepared mattered as much as what went into it, since wet, dried, crushed and sieved each gave a different surface.

Grid of plaster test tiles in different colours and textures — Testing plaster recipes

Exploded axonometric drawing of the roof and panel build-up, labelled layer by layer — Axonometry of the 1:1 prototype

We fitted them into a 1 to 1 mock-up of a typical Gründerzeit attic. Nothing here is a new system. It is proven method adapted to today's surplus, circular, low-impact and reversible.

The mock-up under construction, test panels leaning against pallets in front of the timber frame — Prototype in the Gründerzeit attic

Thank you to Thomas Amann for initiating and guiding this project, to Bregt Hoppenbrouwers, Henri Uijtterhagen, Laurens Bekemans, Ken De Cooman and Julie Moraca of BC architects for their input and criticism, and to Wienerberger and Wiener Linien for supporting the research. The three photographs of the finished prototype are by Paul Sebesta.