ready for a tunnel-formwork-less era?
The other day I attended a valuable session in a large Dutch city, where we evaluated the urban design frameworks with the urban planner, the supervisor and the first architects of a new neighbourhood. The course of the conversation reminded me of Michiel Cohen, former cepezed partner. He answered the question whether Dutch cities should necessarily be built with brick with a relativising counter-question: Could the early medieval man, raised in an almost entirely wooden city, imagine a city of brick?
Many things are going well in the new neighbourhood in question, although the frameworks drawn up have decidedly biased and dated choices. Street walls, for instance, were so starkly sculpted with the Styrofoam cutter that the usual 10 per cent height exemption was not included in the zoning plan. A gross storey height of three metres was used for all building volumes in this regard, befitting common tunnel-box housing. If you are designing a school like us, you can't do anything with this. Another somewhat dated choice concerns the sustainability ambition. These apply to energy management (many PV panels), water retention and anti-heat stress, while attention to CO2 emissions now appears to be much more pressing if we want to build Paris Proof.
Urban planning that capitalises on 'whole life carbon' requires a radically different approach. Emissions during the use phase counts, but the impact of material use and CO2 emissions during construction (and material production) much more so. It means the end of tunnel formwork and the beginning of adaptive construction with renewable and/or reusable materials. Often by applying structural timber, precisely in the building parts with the highest volume impact: construction and facade.
That calls for different building requirements and new parameters, because wooden constructions won't make it with a three-metre floor height, even for houses. Meaning, you can realise substantially fewer floors within the maximum building height, which substantially reduces income, while the costs of these building materials are also substantially higher. This is where we get caught twice, which is why the most important first question is: In setting the boundaries, can we already imagine a wooden city? Because that cities change under the influence of regulations, knowledge and understanding is of all times.
ronald schleurholts
architect-partner cepezed
column: tunnel-formwork-less
