London designers convert invasive species into building materials


In London, two graduates of Central Saint Martins art school have created building tiles from Japanese knotweed and American signal crayfish shells. Brigitte Kock and Irene Roca Moracia chose the two raw materials because they are among the most pernicious invasive species in the UK and their removal improves biodiversity. 

Japanese knotweed can grow into concrete, compromising structural integrity, and overwhelms native plants. The American signal crayfish has similarly overrun native crayfish and their burrows contribute to flooding and infrastructure damage.

“Invasive species removal and control costs the UK around £1.8 billion annually,” Moracia tells Dezeen. “The harvested material is incinerated, buried or trashed. We want to stop this waste. We do not want to create a new industry around this product but to relocate the waste the current system is producing.”

The project is supported by the Maison/0 graduate program by the LVMH group, a luxury goods conglomerate that includes the Dior and Louis Vuitton brands. The program is targeting the development of sustainable building materials for use in its stores. 

The material is made using incinerated knotweed as binder for pulverized crayfish shells, water and gelatin.  “We have played with the percentages and ratios to obtain really strong results,” Moracia adds. “The final colors and textures depend on the curing time and the aggregate’s chemical reactions with the binder and the water.”