Globally, there is a race for the tallest wooden high-rise. Most wooden high-rises are a glued construction of cross laminated timber (CLT) or laminated veneer lumber (LVL), both a type of super plywood. In the Netherlands, the Rijksvastgoedbedrijf is contributing to the transition from skyscraper to 'plyscraper' with a number of ambitious high-rise projects. A transition that has everything to do with the Paris Agreement, as wood stores CO2 and comes from a renewable source, thereby helping to reduce the CO2 footprint already in the construction phase.
Yet it is a surprising choice because wood is not necessarily suitable for high-rise buildings. To make the supporting structure strong enough, substantial columns and beams are needed. In addition, vibration, noise requirements and fire behaviour are a challenge, as is designing a good bio-based façade. Seals, the right package construction and fire resistance have been under a magnifying glass since the Grenfell Towers tragedy in London. This is often solved with a hybrid façade, in which other materials are added. Structures, similarly, are inevitably made up of wood with steel or concrete in the end.
Perhaps a different kind of hybrid might offer a solution too? I then think of the large number of outdated, existing buildings from the last forty years. With a depressing concrete shell, poor spatial quality and outdated façades and installation systems. ' Stripped down', such a shell is a perfect support for extensions that, if cleverly placed, improve the quality of the entire building. These additions and extensions can actually be made in light prefabricated building systems of reused materials and wood.
In this way, you avoid demolition, create sustainable buildings and compact the existing urban fabric in a natural way: three birds with one stone. Which is not to say that the government does not send a powerful signal with a call for tender like the one for plyscrapers, thereby challenging builders and designers to innovate.
ronald schleurholts
architect-partner cepezed
column: Hybride or Plyscrapers?
