An ornament is not a crime

If you leave Vienna on the train and are headed west, you can spot an unknown object on the north side of the tracks when you reach the train station in Unterpurkersdorf, just outside the city limits. A windowless building floating on a pedestal without an indication of its form and function, clad with an industrially created ornament made of aluminium, forces attentive passengers to make a stop they will not regret.

The picture shows the architect of the technical building of Unterpurkersdorf Günter Mohr.

It should be an ornament

With his design of the façade of a technical building of the ÖBB (Austrian Federal Railways), the architect Günter Mohr proved how Adolf Loos’ theory can be refuted with an individual, industrial production of ornaments. Loos is considered a pioneer of modern architecture and believed that ornaments are a waste of labour, material and capital. He even called them a crime. But Loos could not have known which options would open up to architecture due to new technologies and material 110 years later.

In the right place at the right time

When Günter Mohr was looking for an economic, robust and aesthetic façade solution, he came across the extruded aluminium profiles by PREFA. They are available as standard in a ripple profile or a serrated profile.

The first time he heard about the possibility that the extruded aluminium profiles can also be designed individually was during a conversation with PREFA object consultant Christian Wirth at the presentation of the PREFARENZEN book in November 2019. Provided that a minimum quantity is ordered and a corresponding lead time for technical clarifications is taken into consideration, these personalised profiles can be produced in PREFA quality.

Heard and done

This new possibility did not let him go. The next day, he sketched his first ornament consisting of five open circles. The profile was constructed in detail in teamwork and was adapted to the technical requirements of the extrusion press. The PREFA experts, who also printed the first prototypes for practical testing, were responsible for the final touch.

PREFA extruded aluminium profile in the colour bronze

Satisfied customers, a successful project

The presentation to the customer was met with great enthusiasm by everyone involved. One of the reasons was clearly that the profile perfectly bridges the rounded corners of the façade and exhibits a seamless interlocking due to its concealed fixing.

Soon afterwards, the profiles were produced in a length of three metres, powder-coated in the desired colour and mounted on the substructure of the six metre high façade about three months later by an installation team of the company TKSA.

The picture shows the architect of the technical building of Unterpurkersdorf Günter Mohr.

Sustainable and easy to clean

It seems like this experiment has made it possible to invalidate Adolf Loos’ theory once and for all. There was a considerably low use of human working time both during production and the mounting of this extensive ornament. The material is indestructable, but 100% recyclable. And its appearance is timeless. In this short time, it could not be determined yet how its surface responds to dirt. “We expect that there will generally be a sort of self-cleansing process due to the rain. It would also do the building good to undergo high-pressure cleaning at unspecified intervals,” as the architect points out.

Save the date!

A dialogue between architect Günter Mohr and Christian Wirth of PREFA will take place under the title “Free form for the shell of the ÖBB-Technik in Purkersdorf” as part of the architecture festival TURN ON 2021.

Date: Friday, 5 March 2021, 5:25 p.m., large broadcasting hall in the ORF RadioKulturhaus, Vienna.

All lectures will be broadcasted via live stream.
The link will be placed here (no registration, free access).
Due to COVID-19, it will not be possible to attend the event on site.


PREFARENZEN is planning an extensive report on the topic “individual extruded aluminium profiles” with other examples from Switzerland for the next issue of the PREFARENZEN journal.

Technical building, Unterpurkersdorf - details



Building, location:

technical building, Unterpurkersdorf


new construction


Mohr Architekten ZT-GmbH




PREFA extruded aluminium profile


bronze – powder-coated

Further information

  • Text: Carl Bender
  • Photos: © PREFA / Martin Croce