New start for a UU giant: Van Unnik building becomes future-proof

Koen van der Hoorn

In 2019, after many years of discussion, Utrecht University decided not to demolish the iconic high-rise building in the Utrecht Science Park, the Willem C. van Unnik building, but to renovate it. For a long time it had been expected that the sixties giant would be flattened. Built in 1969, the skyscraper is full of asbestos, needs thorough maintenance and no longer meets the wishes of students and researchers. It was clearly time for something new. Koen van der Hoorn, sustainability consultant at the Real Estate & Campus (V&C) department, was one of the driving forces behind UU’s decision to renovate instead.

Van der Hoorn checks some cables on his computer. “Wait a minute, I have three children at home with me..." What should have been an exciting tour of the empty high-rise has become a simple video call in the time of corona.

By renovating, the university is demonstrating that it has chosen to preserve value and promote sustainability rather than take the most advantageous financial option.

Koen van der Hoorn
Real Estate & Campus

More sustainability

Van der Hoorn came to work at the university in 2012, originally 'just' as an asbestos consultant, he says. But when he arrived, sustainability had just become one of the university's spearheads. As a result, his work changed too. Sustainability experts were hired, annual sustainability reports appeared and sustainability targets were set for the entire university. The idea was that every student should be involved with sustainability from now on. The university also wanted its buildings and business operations to reflect its own research into sustainability – research in which UU scientists excel. And so van der Hoorn's work shifted from asbestos to sustainable building, renovation and demolition.

Vision of future-proof construction

This trend towards sustainability also led to a vision of future-proof construction in 2019. From now on, new UU buildings will be circular, flexible, healthy and energy-generating. “The Executive Board's decision to renovate the Van Unnik building is a tangible expression of this vision,” explains van der Hoorn.

Nothing wrong with the frame

The foundations and the concrete frame of the existing tower will remain in place. Architectural investigations revealed that there was nothing wrong with either. The rest will be dismantled and rebuilt. “That has to happen, because there's asbestos in a lot of places where you can't simply remove it.” Does that still count as circular and sustainable, when you just recycle the foundations and the frame? Yes, it does. “This alone will save about 3,100 tonnes of CO.” That is about the same amount of CO that the university annually compensates for trips made by exchange students. Not to mention all the CO necessary for the construction process itself: the builders who come to work every day and trucks that drive in and out with heavy building materials.

A few days later, van der Hoorn followed up our conversation with an email: "I've just received the first estimate of CO savings for the Kruyt building!" The Kruyt building is the 1960s companion to the Van Unnik building, a little further down the road in the Utrecht Science Park (USP), and almost twice as big in terms of surface area. Its frame is still good as well, so the building is also going to be renovated. “That will save as much as 11,000 tonnes of CO!"

Front view of the Willem C. van Unnik building

Prompted by asbestos

Van der Hoorn was involved in the project from the beginning. As an asbestos consultant, his primary concern was how to deal with the asbestos in the best and safest way possible, both while the building was in use and after. That meant he got to know the building very well and had gathered thorough data covering every possible scenario for demolition, renovation and recycling. While doing so, he began to see the potential of renovation. He ended up actively lobbying for this option.

Decision to preserve value

Van der Hoorn is now very proud. “By renovating, the university is demonstrating that it has chosen to preserve value and promote sustainability rather than – by definition – taking the most advantageous financial option.” Because renovation and refurbishment are not necessarily cheaper. It also means that a unique, iconic building can be preserved. Its original name, Transitorium II, refers to the university’s transition from the city centre to De Uithof in the 1960s. The Van Unnik was one of the first buildings the university had built there.

The elevators on the ground floor of the Willem C. van Unnik building
The Van Unnik under construction in the 1960s.

Collaboration with scientists

Van der Hoorn is looking forward to working with scientists in the near future. He hopes the renovated high-rise building will be finished by 2027. That still leaves enough time to work with UU scientists to ensure that, when in use, the building will be as sustainable and circular as possible: windows with integrated solar panels, 'green' façades, walls made of fungal mycelium or other sustainable materials and applied nudging research aimed at the users of the building: van der Hoorn wants it all. The design has yet to be made. So let's get started. The demolition of the low-rise building is due to happen first, in 2021.