Volcanic ash tiles

Clay Technology magazine
7 Jun 2019

Designers have created a collection of surface tiles glazed with volcanic ash from Mount Etna in Italy. Shardell Joseph finds out more.

Design duo Formafantasma, Netherlands, and architectural materials company Dzek have introduced a tile collection that incorporates volcanic ash, which was on display at Milan Design Week in April 2019.

After years of experimentation, Formafantasma designers Andrea Trimarchi and Simone Farresin have created five shades of volcanic glaze, each containing a different amount of finely ground ash. The collection of porcelain tiles, called ExCincere, is rectangular with yellow-brown tones, suitable for both indoor and outdoor surfaces.

‘Generally, we are never retro in our work, but this just came out and it’s totally 1970s, it definitely speaks of the decade,’ said the designers.

The volcanic ash used to create the glaze, found on Mount Etna, contains fragments of pulverised rock, including basalt – a magnesium and iron-rich volcanic rock created by the rapid cooling of lava.

Formafantasma compared Mount Etna to a mine without miners, excavating itself to expose its raw materials.

Dzek views ExCinere as a new take on the tradition of using volcanic lava as a building material, illustrating it as a manifest of the enduring attraction between humans and the impossible force of nature.

Formafantasma described the collection as a demonstration of the full potential of volcanic ash, which is ‘naturally occurring, self-generating and abundant’.

How they were made

Formafantasma and Dzek constructed the tiles based on their existing research from their 2014 project De Natura Fossilium, which was a series of homeware objects. Because of the high metal-oxide content, ash becomes a complex and unpredictable substance to work with.

The process of examining the exact balance of the porcelain tile, ash glaze, firing temperature and method to prevent the pieces cracking or exploding during the firing process took the designers nearly two years.

‘Although volcanic ash and basalt rock may appear inert, their metal-oxide content makes them complex to work with,’ said Dzek. ‘The material has its own will and you have to allow it to go where it needs to.

‘Identifying the right balance of volcanic ash percentages, granule sizes, densities, firing temperatures, firing methods and clay body took almost 20 months to be exact.’

Before creating the new tile collection, the designers experimented with creating bricks from volcanic glass. Although successful in its development, they were impractical and glassmakers were wary when working with them, due to concerns that the volcanic ash from the black glass would easily contaminate a furnace affecting other glass products.

The next experiment from Formafantasma was painting ash-based glazes onto terracotta bricks. By increasing the temperature of a kiln from 2,460 to 2,515°C, the designers realised the ash glazes would activate and create beautiful colour textures. However, these materials were very rough to touch, which would be suitable for exterior building material but not for tiling a bathroom or kitchen.

The designers landed on a series of five different glazes, called ExCincere, each of which has a different percentage of ash. The lightest, which have a warm beige colour are composed of about 25% of very finely ground ash, while the deepest browns are more than 80% coarse ash that is the consistency of sea salt. These glazes were then applied onto the porcelain tile bodies and fired in a kiln.

‘The lighter glazes use extremely fine ash powders. The glazes become increasingly darker and more specked as the ash particles increase in size and frequency,’ said Dzek.

The full range of colours of the collection was displayed in Milan in an installation at a satellite of the Alcova site on Via Popoli Uniti.

Having experimented with volcanic materials before, the designers previously created clocks, bowls, tables, stools, glasses and textiles with the ash substance. These differ from the tiles, however, as they were bespoke collections rather than a product that could be scaled up. The designers and Dzek have see the tiles as a new way of using volcanic material, and created a process to manufacture it in small batches.

Currently, they are working on streamlining the production process, which relies on significant manual labour, to bring down the price, and are aiming to start filling orders by this summer.