Off campus

The Heritage research group at Architecture stands up for houses in Delft

Protect Delft’s so-called Diagoon Houses, designed by the architect and former TU Delft Professor Herman Hertzberger. The Heritage and Architecture research group at the Faculty of Architecture and the Built Environment submitted this unique plea in a letter to the Municipality.

(Photo: Robert von der Nahmer)

Professor Wessel de Jonge and research group leader Wido Quist express their concerns about the Diagoon Houses on the Gebbenlaan that were designed by TU Delft Professor Emeritus Herman Hertzberger. If the Municipality does not prioritise granting the complex the heritage status, it could take another four years before they are even considered. De Jonge and Quist are worried that this will be too late and that, in the meantime, new owners may change the design.

They see that one of the eight – from the start badly insulated – houses built in 1970-1971 has recently closed the gas connection ‘with major consequences for the distinctive house’. They write (in Dutch) that ‘Renovation unavoidably brings far-reaching changes, and even more so if no municipal decrees are used to regulate renovation. The houses are vulnerable to changes done without due care and there is a real chance that the houses will gradually be irreversibly changed.’

(Photo: Jan Bartelmans)
Previous pleas

The Heritage and Architecture research group stands behind the previously submitted plea by the Erfgoedvereniging Heemschut (Heemschut heritage foundation) to speed up the process of giving the Diagoonwoningen a heritage status. The Erfgoedvereniging Heemschut submitted the last application in October 2023. The Municipality has not yet responded to the application.

Responding to questions from Delta, the Municipality said it recognised ‘the special character’ of the houses. ‘That is why they are already protected in the zoning plan as cultural-historical value.’

Delft confirms Heemschut’s repeated request to designate them as municipal monuments and also reports that a conversation took place in November 2023, in which it announced it would inform the association in early 2024. ‘The Municipality is preparing to process this request.’

According to the spokesperson, the Municipality now wants to hear the views of the residents of the Diagoon Houses. ‘Therefore, we are happy to engage with the residents, who have now received a letter announcing that the Municipality will invite them to this discussion.’ Enquiries show that that letter did indeed reach the residents on 28 February.



Quist says that this is the first time that his research group has expressed itself in a letter to the Municipality or to any Government body. In an email he states ‘Given the Delft context and the connection between the houses and Herman Hertzberger, who is Professor Emeritus at TU Delft, it is important that we do this now’.

What makes the Diagoon Houses so special?

Wido Quist explains that they are exceptional because they ‘are the most structuralist homes built to date and that are still doing what they were built for’. Another aspect is that they were designed by Herman Hertzberger, one of the best-known advocates of structuralism, he adds.

He says that even when they were first built, the homes were famous for their experimental character. In Quist’s eyes, the houses are unique because they clearly reflect the era of the late 1960s and the early 1970s.

  • Want to know more about the Diagoon Houses? Check the website, or order the monograph.
Design studio

The Diagoon Houses will be the subject of a master’s design studio at Architecture and the Built Environment in the fourth quarter of this academic year. ‘We will concentrate on the spatial quality of the interior in relation to the exterior, and its potential for adaptation in terms of greater sustainability,’ explains Quist.

  • The Diagoon Houses overlook the Duwo student flat on the Van Hasseltlaan. A lengthy renovation is planned there that local residents and students are not looking forward to.
Editor in chief Saskia Bonger

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