the greenest week of the year

cepezed aims to design buildings that fit within planetary boundaries. That is why we organised Green Week for the fourth time, a week that inspires, educates, keeps us on our toes and shows how serious cepezed is about sustainability. This year, CO₂ reduction was an important theme, but not the only one.

urgency
‘The entire team is aware of the environmental issues we face,’ says cepezed partner Ronald Schleurholts. ‘But it is not always easy to maintain high sustainability ambitions during the design process and during construction. Green Week strengthens us with inspiration and provides information about new tools. With a programme that is broader and more specialised than our daily routine, we emphasise the urgency once again and show that sustainable architecture offers exciting new opportunities. As the development of sustainable construction is not standing still. And the process is also changing – collaboration is essential in sustainable construction.’

varied programme
We kicked off with a presentation on figures: our CO₂ experts calculated the CO₂ performance of eight projects. On Wednesday evening, we watched the film Hacer mucho con poco (Doing a lot with little). On Thursday afternoon, after a keynote speech by Ad Kil of RO&AD Architects, there was a choice of four workshops. And throughout the week, a temporary sustainability library in the hall offered the opportunity to browse each other's books and borrow them.

large green footprint
A building is always part of one or more systems, Ad Kil told us in his lecture. Using examples such as the Tij bird observatory along the Haringvliet, the office of the Deltawind energy cooperative, and the field station in the Hedwige Polder, he showed how his firm designs buildings “with the largest possible green footprint”. In principle, RO&AD does not use new building elements produced with fossil resources. The examples mentioned are circular, biobased and, if possible, geo-based. For example, the observatory was covered with reeds from the surrounding area.

perseverance pays off
If the designs presented by Ad illustrate anything, it is that perseverance pays off. For example, a Dutch structural engineer at first calculated that the egg-shaped wooden frame of Tij could only be realised with steel joints, but two retired Finnish structural engineers proved otherwise. In the end it is completely composed of prefabricated wooden elements that are fastened with wooden pins. At RO&AD, collaboration often means working together on the construction site. “Being there as an architect is crucial,” says Ad, “because so many decisions are still made during construction. We learn a lot from every project.”

daylight driven design
The four workshops offered the opportunity to learn more about daylight-driven design, sustainable outdoor space design, biobased façade materials, and climate engineering. The design workshop led by landscape architect Erica Chladová (LMNL office) was the most dynamic of the four. Following her brief on green garden design, various submitted references were discussed and three teams were formed, each of which created a model to improve our office's currently rather stony outdoor spaces. This was also a nice way to get to know colleagues better. cepezed architects Jamal van Kastel and Frank Smit showed in their workshop what parametric design and BIM can mean for daylight calculations. It is no coincidence that “daylight-driven design” is a variation on “data-driven design”, something that cepezed is increasingly focusing on with specialists such as Frank and Jamal. For the workshop, they used the design of the HvA Gezondheidscampus (AUAS Health Campus) as an example.

biobased facades
Thomas Pijnenborgh, founder of Groene Bouwmaterialen, brought along the kit that had been on display at Dutch Design Week this year. Through our questions about the samples, he came up with some interesting examples. Such as that of BC Materials, the materials branch of Brussels Cooperation, which developed a cast floor using low-grade loam that can be extracted from construction sites in Brussels. Other questions highlighted issues that cepezed often encounters in practice: regulations, including those concerning the combination of new, biobased materials. Fortunately, Thomas was also familiar with this topic. He emphasised that introducing biobased materials early in the design process makes them easier to apply, something that we at cepezed are already actively directing towards.

climate engineering
In Christian Frenzel's workshop, he reviewed a series of examples that he had worked on with his firm Transsolar. They ranged from renovation to new construction and varied in scale. In all these projects, Transsolar focused on tackling operational carbon and improving user comfort. Christian showed how much of a difference the organisation of the programme, but also aspects such as thermal mass, adiabatic cooling (where heat is extracted from the air), night ventilation and heat storage can make to CO₂ emissions.

refuse
In the plenary feedback session, the models were presented and we shared the most important points from the workshops. For example, that choosing bio-based materials can be expensive, but using them will regulate the indoor climate more cheaply. In any case, the indoor climate often appears to be “overdimensioned”. Sometimes it is better to take a step back, rather than constantly adding materials or installations. And so this Green Week ended with the very first step on the R ladder: refuse.

Ivan Avdić, Dick Klijn and Sonja Draskovic, thank you very much, puno hvala, for putting together and organising the Green Week 2025 programme.