Sponge furniture that grows – just add water

Researchers at Swiss design school ECAL designed a series of flat-pack furniture made of a cellulose sponge material, that grows when soaked in water.

Called Under Pressure Solutions (UPS), the project imagines a lightweight furniture system made of a biobased and biodegradable material. The sponge material is made of wood offcuts. It gains it strength from the cellulose fibres that reinforce the tree. The material was first developed in the 1940s by chemically dissolving wood and processing it in a similar way as to make viscose and other cellulose textiles. The material is commonly used for household, medical and make-up sponges and is solt in standardised, dehydrated sheets.

To make the material even more absorbent, mirabilite (also known as Glauber’s salt) is added for the furniture.

The objects can be shipped in a compressed form. Once they have reached their destination, they are moistened, allowing them to expand and reconfigure themselves, no mechanical assembly needed. In water, the dehydrated sponge sheets expand to around 10 times their original size.

Once in shape, the sponge is wrung out and left to dry and harden, to create sturdy, self-supporting furniture. If the furniture is deformed or damages, it can be moistened to make the material soft again.

During Milan Design Week (16-21 April 2024), the results of the project, led by five industrial designers teaching at ECAL, as well as objects designed by Master Product Design students, were displayed.

Photos: Jasmine Deporta